Abstract

Scattering-type scanning near-field optical microscopy (SNOM) offers the possibility to analyze material properties like strain in crystals at the nanoscale. In this paper we introduce a SNOM setup employing a newly developed tunable broadband laser source with a covered spectral range from 9 µm to 16 µm. This setup allows for the first time optical analyses of the crystal structure of gallium nitride (GaN) at the nanometer scale by excitation of a near-field phonon resonance around 14.5 µm. On the example of an artificially induced stress field within a GaN wafer, we present a method for a 2D visualization of small deviations in the crystal structure, which allows for fast qualitative characterizations. Subsequently, the stress levels at chosen points were quantified by recording complex near-field spectra and correlating them with theoretical model calculations. Applied to the cross-section of a heteroepitaxially grown GaN wafer, we finally demonstrate the capability of our setup to analyze the relaxation of the crystal structure along the growth axis with a nanometer spatial resolution.

© 2014 Optical Society of America

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References

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  1. F. Keilmann and R. Hillenbrand, “Near-field nanoscopy by elastic light scattering from a tip,” in A. Zayats and D. Richards, eds., Nano-Optics and Near-Field Optical Microscopy (Artech House, 2009), Chap. 11, pp. 235–265.
  2. T. Taubner, R. Hillenbrand, and F. Keilmann, “Nanoscale polymer recognition by spectral signature in scattering infrared near-field microscopy,” Appl. Phys. Lett. 85(21), 5064–5066 (2004).
    [Crossref]
  3. A. J. Huber, J. Wittborn, and R. Hillenbrand, “Infrared spectroscopic near-field mapping of single nanotransistors,” Nanotechnology 21(23), 235702 (2010).
    [Crossref] [PubMed]
  4. M. Brehm, T. Taubner, R. Hillenbrand, and F. Keilmann, “Infrared spectroscopic mapping of single nanoparticles and viruses at nanoscale resolution,” Nano Lett. 6(7), 1307–1310 (2006).
    [Crossref] [PubMed]
  5. A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Material-specific infrared recognition of single sub-10 nm particles by substrate-enhanced scattering-type near-field microscopy,” Nano Lett. 7(10), 3177–3181 (2007).
    [Crossref] [PubMed]
  6. A. Huber, N. Ocelic, T. Taubner, and R. Hillenbrand, “Nanoscale resolved infrared probing of crystal structure and of plasmon-phonon coupling,” Nano Lett. 6(4), 774–778 (2006).
    [Crossref] [PubMed]
  7. A. J. Huber, A. Ziegler, T. Köck, and R. Hillenbrand, “Infrared nanoscopy of strained semiconductors,” Nat. Nanotechnol. 4(3), 153–157 (2009).
    [Crossref] [PubMed]
  8. A. M. Gigler, A. J. Huber, M. Bauer, A. Ziegler, R. Hillenbrand, and R. W. Stark, “Nanoscale residual stress-field mappingaround nanoindents in SiCby IR s-SNOM and confocal Raman microscopy,” Opt. Express 17(25), 22351–22357 (2009).
    [Crossref] [PubMed]
  9. A. J. Huber, D. Kazantsev, F. Keilmann, J. Wittborn, and R. Hillenbrand, “Simultaneous IR material recognition and conductivity mapping by nanoscale near-field microscopy,” Adv. Mater. 19(17), 2209–2212 (2007).
    [Crossref]
  10. T. Taubner, R. Hillenbrand, and F. Keilmann, “Performance of visible and mid-infrared scattering-type near-field optical microscopes,” J. Microsc. 210(3), 311–314 (2003).
    [Crossref] [PubMed]
  11. J. M. Hoffmann, B. Hauer, and T. Taubner, “Antenna-enhanced infrared near-field nanospectroscopy of a polymer,” Appl. Phys. Lett. 101(19), 193105 (2012).
    [Crossref]
  12. F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
    [Crossref] [PubMed]
  13. R. Hillenbrand, T. Taubner, and F. Keilmann, “Phonon-enhanced light matter interaction at the nanometre scale,” Nature 418(6894), 159–162 (2002).
    [Crossref] [PubMed]
  14. N. Ocelic and R. Hillenbrand, “Subwavelength-scale tailoring of surface phonon polaritons by focused ion-beam implantation,” Nat. Mater. 3(9), 606–609 (2004).
    [Crossref] [PubMed]
  15. M. Kuball, “Raman spectroscopy of GaN, AlGaN and AlN for process and growth monitoring/control,” Surf. Interface Anal. 31(10), 987–999 (2001).
    [Crossref]
  16. S. Amarie and F. Keilmann, “Broadband-infrared assessment of phonon resonance in scattering-type near-field microscopy,” Phys. Rev. B 83(4), 045404 (2011).
    [Crossref]
  17. I. M. Watson, “Metal organic vapour phase epitaxy of AlN, GaN, InN and their alloys: A key chemical technology for advanced device applications,” Coord. Chem. Rev. 257(13-14), 2120–2141 (2013).
    [Crossref]
  18. B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
    [Crossref]
  19. J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
    [Crossref]
  20. Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
    [Crossref] [PubMed]
  21. I. M. Craig, M. S. Taubman, A. S. Lea, M. C. Phillips, E. E. Josberger, and M. B. Raschke, “Infrared near-field spectroscopy of trace explosives using an external cavity quantum cascade laser,” Opt. Express 21(25), 30401–30414 (2013).
    [Crossref] [PubMed]
  22. Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
    [Crossref] [PubMed]
  23. X. G. Xu, M. Rang, I. M. Craig, and M. B. Raschke, “Pushing the sample-size limit of infrared vibrational nanospectroscopy: from monolayer toward single molecule sensitivity,” J. Phys. Chem. Lett. 3(13), 1836–1841 (2012).
    [Crossref]
  24. F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, “Infrared-spectroscopic nanoimaging with a thermal source,” Nat. Mater. 10(5), 352–356 (2011).
    [Crossref] [PubMed]
  25. S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
    [Crossref]
  26. S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
    [Crossref] [PubMed]
  27. P. Hermann, A. Hoehl, P. Patoka, F. Huth, E. Rühl, and G. Ulm, “Near-field imaging and nano-Fourier-transform infrared spectroscopy using broadband synchrotron radiation,” Opt. Express 21(3), 2913–2919 (2013).
    [Crossref] [PubMed]
  28. J. Wueppen, B. Jungbluth, T. Taubner, and P. Loosen, “Ultrafast tunable mid IR source,” in Proceedings of IEEE IRMMW-THz (Houston, TX, 2011).
  29. A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Analytical model for quantitative prediction of material contrasts in scattering-type near-field optical microscopy,” Opt. Express 15(14), 8550–8565 (2007).
    [Crossref] [PubMed]
  30. N. Ocelic, “Quantitative near-field phonon-polariton spectroscopy,” Dissertation, TU München, 2007.
  31. J. M. Wagner and F. Bechstedt, “Properties of strained wurtzite GaN and AlN: Ab initio studies,” Phys. Rev. B 66(11), 115202 (2002).
    [Crossref]
  32. G. Yu, N. L. Rowell, and D. J. Lockwood, “Anisotropic infrared optical properties of GaN and sapphire,” J. Vac. Sci. Technol. A 22(4), 1110–1114 (2004).
    [Crossref]
  33. A. S. Barker and M. Ilegems, “Infrared lattice vibrations and free-electron dispersion in GaN,” Phys. Rev. B 7(2), 743–750 (1973).
    [Crossref]
  34. F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
    [Crossref]
  35. N. Ocelic, A. Huber, and R. Hillenbrand, “Pseudoheterodyne detection for background-free near-field spectroscopy,” Appl. Phys. Lett. 89(10), 101124 (2006).
    [Crossref]
  36. I. Vurgaftman and J. R. Meyer, “Band paramters for nitrogen-containing semiconductors,” J. Appl. Phys. 94(6), 3675–3696 (2003).
    [Crossref]
  37. C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
    [Crossref]
  38. T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
    [Crossref]
  39. X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
    [Crossref]
  40. T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
    [Crossref]
  41. J. S. Xue, Y. Hao, J. C. Zhang, and J. Y. Ni, “Comparative study of different properties of GaN films grown on (0001) sapphire using high and low temperature AlN interlayers,” Chin. Phys. B 19(5), 057203 (2010).
    [Crossref]
  42. R. Seitz, T. Monteiro, E. Pereira, and M. Di Forte-Poisson, “Strain relaxation in GaN films as a function of growth direction and buffer layer measured by Raman spectroscopy,” Phys. Status Solidi, A Appl. Res. 176(1), 661–664 (1999).
    [Crossref]
  43. S. Y. Huang and J. R. Yang, “A transmission electron microscopy observation of dislocations in GaN grown on (0001) sapphire by metal organic chemical vapor deposition,” Jpn. J. Appl. Phys. 47(10), 7998–8002 (2008).
    [Crossref]

2013 (4)

I. M. Watson, “Metal organic vapour phase epitaxy of AlN, GaN, InN and their alloys: A key chemical technology for advanced device applications,” Coord. Chem. Rev. 257(13-14), 2120–2141 (2013).
[Crossref]

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

P. Hermann, A. Hoehl, P. Patoka, F. Huth, E. Rühl, and G. Ulm, “Near-field imaging and nano-Fourier-transform infrared spectroscopy using broadband synchrotron radiation,” Opt. Express 21(3), 2913–2919 (2013).
[Crossref] [PubMed]

I. M. Craig, M. S. Taubman, A. S. Lea, M. C. Phillips, E. E. Josberger, and M. B. Raschke, “Infrared near-field spectroscopy of trace explosives using an external cavity quantum cascade laser,” Opt. Express 21(25), 30401–30414 (2013).
[Crossref] [PubMed]

2012 (4)

J. M. Hoffmann, B. Hauer, and T. Taubner, “Antenna-enhanced infrared near-field nanospectroscopy of a polymer,” Appl. Phys. Lett. 101(19), 193105 (2012).
[Crossref]

F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
[Crossref] [PubMed]

Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
[Crossref] [PubMed]

X. G. Xu, M. Rang, I. M. Craig, and M. B. Raschke, “Pushing the sample-size limit of infrared vibrational nanospectroscopy: from monolayer toward single molecule sensitivity,” J. Phys. Chem. Lett. 3(13), 1836–1841 (2012).
[Crossref]

2011 (3)

F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, “Infrared-spectroscopic nanoimaging with a thermal source,” Nat. Mater. 10(5), 352–356 (2011).
[Crossref] [PubMed]

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

S. Amarie and F. Keilmann, “Broadband-infrared assessment of phonon resonance in scattering-type near-field microscopy,” Phys. Rev. B 83(4), 045404 (2011).
[Crossref]

2010 (3)

A. J. Huber, J. Wittborn, and R. Hillenbrand, “Infrared spectroscopic near-field mapping of single nanotransistors,” Nanotechnology 21(23), 235702 (2010).
[Crossref] [PubMed]

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

J. S. Xue, Y. Hao, J. C. Zhang, and J. Y. Ni, “Comparative study of different properties of GaN films grown on (0001) sapphire using high and low temperature AlN interlayers,” Chin. Phys. B 19(5), 057203 (2010).
[Crossref]

2009 (2)

2008 (2)

S. Y. Huang and J. R. Yang, “A transmission electron microscopy observation of dislocations in GaN grown on (0001) sapphire by metal organic chemical vapor deposition,” Jpn. J. Appl. Phys. 47(10), 7998–8002 (2008).
[Crossref]

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

2007 (4)

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Material-specific infrared recognition of single sub-10 nm particles by substrate-enhanced scattering-type near-field microscopy,” Nano Lett. 7(10), 3177–3181 (2007).
[Crossref] [PubMed]

A. J. Huber, D. Kazantsev, F. Keilmann, J. Wittborn, and R. Hillenbrand, “Simultaneous IR material recognition and conductivity mapping by nanoscale near-field microscopy,” Adv. Mater. 19(17), 2209–2212 (2007).
[Crossref]

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Analytical model for quantitative prediction of material contrasts in scattering-type near-field optical microscopy,” Opt. Express 15(14), 8550–8565 (2007).
[Crossref] [PubMed]

2006 (4)

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

A. Huber, N. Ocelic, T. Taubner, and R. Hillenbrand, “Nanoscale resolved infrared probing of crystal structure and of plasmon-phonon coupling,” Nano Lett. 6(4), 774–778 (2006).
[Crossref] [PubMed]

M. Brehm, T. Taubner, R. Hillenbrand, and F. Keilmann, “Infrared spectroscopic mapping of single nanoparticles and viruses at nanoscale resolution,” Nano Lett. 6(7), 1307–1310 (2006).
[Crossref] [PubMed]

N. Ocelic, A. Huber, and R. Hillenbrand, “Pseudoheterodyne detection for background-free near-field spectroscopy,” Appl. Phys. Lett. 89(10), 101124 (2006).
[Crossref]

2004 (3)

G. Yu, N. L. Rowell, and D. J. Lockwood, “Anisotropic infrared optical properties of GaN and sapphire,” J. Vac. Sci. Technol. A 22(4), 1110–1114 (2004).
[Crossref]

T. Taubner, R. Hillenbrand, and F. Keilmann, “Nanoscale polymer recognition by spectral signature in scattering infrared near-field microscopy,” Appl. Phys. Lett. 85(21), 5064–5066 (2004).
[Crossref]

N. Ocelic and R. Hillenbrand, “Subwavelength-scale tailoring of surface phonon polaritons by focused ion-beam implantation,” Nat. Mater. 3(9), 606–609 (2004).
[Crossref] [PubMed]

2003 (2)

T. Taubner, R. Hillenbrand, and F. Keilmann, “Performance of visible and mid-infrared scattering-type near-field optical microscopes,” J. Microsc. 210(3), 311–314 (2003).
[Crossref] [PubMed]

I. Vurgaftman and J. R. Meyer, “Band paramters for nitrogen-containing semiconductors,” J. Appl. Phys. 94(6), 3675–3696 (2003).
[Crossref]

2002 (2)

J. M. Wagner and F. Bechstedt, “Properties of strained wurtzite GaN and AlN: Ab initio studies,” Phys. Rev. B 66(11), 115202 (2002).
[Crossref]

R. Hillenbrand, T. Taubner, and F. Keilmann, “Phonon-enhanced light matter interaction at the nanometre scale,” Nature 418(6894), 159–162 (2002).
[Crossref] [PubMed]

2001 (2)

M. Kuball, “Raman spectroscopy of GaN, AlGaN and AlN for process and growth monitoring/control,” Surf. Interface Anal. 31(10), 987–999 (2001).
[Crossref]

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

1999 (1)

R. Seitz, T. Monteiro, E. Pereira, and M. Di Forte-Poisson, “Strain relaxation in GaN films as a function of growth direction and buffer layer measured by Raman spectroscopy,” Phys. Status Solidi, A Appl. Res. 176(1), 661–664 (1999).
[Crossref]

1996 (2)

C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
[Crossref]

F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
[Crossref]

1995 (1)

T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
[Crossref]

1973 (1)

A. S. Barker and M. Ilegems, “Infrared lattice vibrations and free-electron dispersion in GaN,” Phys. Rev. B 7(2), 743–750 (1973).
[Crossref]

Amarie, S.

F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
[Crossref] [PubMed]

S. Amarie and F. Keilmann, “Broadband-infrared assessment of phonon resonance in scattering-type near-field microscopy,” Phys. Rev. B 83(4), 045404 (2011).
[Crossref]

Andreev, G. O.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Aulombard, R. L.

F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
[Crossref]

Bao, W.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Barker, A. S.

A. S. Barker and M. Ilegems, “Infrared lattice vibrations and free-electron dispersion in GaN,” Phys. Rev. B 7(2), 743–750 (1973).
[Crossref]

Basov, D. N.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Bassim, N. D.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Bauer, M.

Bechstedt, F.

J. M. Wagner and F. Bechstedt, “Properties of strained wurtzite GaN and AlN: Ab initio studies,” Phys. Rev. B 66(11), 115202 (2002).
[Crossref]

Böttcher, T.

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

Brehm, M.

M. Brehm, T. Taubner, R. Hillenbrand, and F. Keilmann, “Infrared spectroscopic mapping of single nanoparticles and viruses at nanoscale resolution,” Nano Lett. 6(7), 1307–1310 (2006).
[Crossref] [PubMed]

Briot, O.

F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
[Crossref]

Caldwell, J. D.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Castro-Neto, A. H.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Cebula, M.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

Chierchia, R.

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

Craig, I. M.

I. M. Craig, M. S. Taubman, A. S. Lea, M. C. Phillips, E. E. Josberger, and M. B. Raschke, “Infrared near-field spectroscopy of trace explosives using an external cavity quantum cascade laser,” Opt. Express 21(25), 30401–30414 (2013).
[Crossref] [PubMed]

X. G. Xu, M. Rang, I. M. Craig, and M. B. Raschke, “Pushing the sample-size limit of infrared vibrational nanospectroscopy: from monolayer toward single molecule sensitivity,” J. Phys. Chem. Lett. 3(13), 1836–1841 (2012).
[Crossref]

Cvitkovic, A.

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Analytical model for quantitative prediction of material contrasts in scattering-type near-field optical microscopy,” Opt. Express 15(14), 8550–8565 (2007).
[Crossref] [PubMed]

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Material-specific infrared recognition of single sub-10 nm particles by substrate-enhanced scattering-type near-field microscopy,” Nano Lett. 7(10), 3177–3181 (2007).
[Crossref] [PubMed]

Demangeot, F.

F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
[Crossref]

Di Forte-Poisson, M.

R. Seitz, T. Monteiro, E. Pereira, and M. Di Forte-Poisson, “Strain relaxation in GaN films as a function of growth direction and buffer layer measured by Raman spectroscopy,” Phys. Status Solidi, A Appl. Res. 176(1), 661–664 (1999).
[Crossref]

Ding, Y.

Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
[Crossref] [PubMed]

Dominguez, G.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Eddy, C. R.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Einfeldt, S.

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

Eng, L. M.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

Fei, Z.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Figge, S.

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

Fogler, M. M.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Frandon, J.

F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
[Crossref]

Gigler, A. M.

Gil, B.

F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
[Crossref]

Glembocki, O. J.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Govyadinov, A.

F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
[Crossref] [PubMed]

Grafström, S.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

Guo, X.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Hahn, H.

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

Hao, Y.

J. S. Xue, Y. Hao, J. C. Zhang, and J. Y. Ni, “Comparative study of different properties of GaN films grown on (0001) sapphire using high and low temperature AlN interlayers,” Chin. Phys. B 19(5), 057203 (2010).
[Crossref]

Härtling, T.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

Hauer, B.

J. M. Hoffmann, B. Hauer, and T. Taubner, “Antenna-enhanced infrared near-field nanospectroscopy of a polymer,” Appl. Phys. Lett. 101(19), 193105 (2012).
[Crossref]

Heinke, H.

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

Helm, M.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

Henry, R. L.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Hermann, P.

Heuken, M.

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

Hillenbrand, R.

F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
[Crossref] [PubMed]

F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, “Infrared-spectroscopic nanoimaging with a thermal source,” Nat. Mater. 10(5), 352–356 (2011).
[Crossref] [PubMed]

A. J. Huber, J. Wittborn, and R. Hillenbrand, “Infrared spectroscopic near-field mapping of single nanotransistors,” Nanotechnology 21(23), 235702 (2010).
[Crossref] [PubMed]

A. J. Huber, A. Ziegler, T. Köck, and R. Hillenbrand, “Infrared nanoscopy of strained semiconductors,” Nat. Nanotechnol. 4(3), 153–157 (2009).
[Crossref] [PubMed]

A. M. Gigler, A. J. Huber, M. Bauer, A. Ziegler, R. Hillenbrand, and R. W. Stark, “Nanoscale residual stress-field mappingaround nanoindents in SiCby IR s-SNOM and confocal Raman microscopy,” Opt. Express 17(25), 22351–22357 (2009).
[Crossref] [PubMed]

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Analytical model for quantitative prediction of material contrasts in scattering-type near-field optical microscopy,” Opt. Express 15(14), 8550–8565 (2007).
[Crossref] [PubMed]

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Material-specific infrared recognition of single sub-10 nm particles by substrate-enhanced scattering-type near-field microscopy,” Nano Lett. 7(10), 3177–3181 (2007).
[Crossref] [PubMed]

A. J. Huber, D. Kazantsev, F. Keilmann, J. Wittborn, and R. Hillenbrand, “Simultaneous IR material recognition and conductivity mapping by nanoscale near-field microscopy,” Adv. Mater. 19(17), 2209–2212 (2007).
[Crossref]

N. Ocelic, A. Huber, and R. Hillenbrand, “Pseudoheterodyne detection for background-free near-field spectroscopy,” Appl. Phys. Lett. 89(10), 101124 (2006).
[Crossref]

M. Brehm, T. Taubner, R. Hillenbrand, and F. Keilmann, “Infrared spectroscopic mapping of single nanoparticles and viruses at nanoscale resolution,” Nano Lett. 6(7), 1307–1310 (2006).
[Crossref] [PubMed]

A. Huber, N. Ocelic, T. Taubner, and R. Hillenbrand, “Nanoscale resolved infrared probing of crystal structure and of plasmon-phonon coupling,” Nano Lett. 6(4), 774–778 (2006).
[Crossref] [PubMed]

T. Taubner, R. Hillenbrand, and F. Keilmann, “Nanoscale polymer recognition by spectral signature in scattering infrared near-field microscopy,” Appl. Phys. Lett. 85(21), 5064–5066 (2004).
[Crossref]

N. Ocelic and R. Hillenbrand, “Subwavelength-scale tailoring of surface phonon polaritons by focused ion-beam implantation,” Nat. Mater. 3(9), 606–609 (2004).
[Crossref] [PubMed]

T. Taubner, R. Hillenbrand, and F. Keilmann, “Performance of visible and mid-infrared scattering-type near-field optical microscopes,” J. Microsc. 210(3), 311–314 (2003).
[Crossref] [PubMed]

R. Hillenbrand, T. Taubner, and F. Keilmann, “Phonon-enhanced light matter interaction at the nanometre scale,” Nature 418(6894), 159–162 (2002).
[Crossref] [PubMed]

Hobart, K. D.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Hoehl, A.

Hoffmann, J. M.

J. M. Hoffmann, B. Hauer, and T. Taubner, “Antenna-enhanced infrared near-field nanospectroscopy of a polymer,” Appl. Phys. Lett. 101(19), 193105 (2012).
[Crossref]

Holländer, B.

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

Holm, R. T.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Hommel, D.

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

Hu, Y.

Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
[Crossref] [PubMed]

Huang, S. Y.

S. Y. Huang and J. R. Yang, “A transmission electron microscopy observation of dislocations in GaN grown on (0001) sapphire by metal organic chemical vapor deposition,” Jpn. J. Appl. Phys. 47(10), 7998–8002 (2008).
[Crossref]

Huber, A.

A. Huber, N. Ocelic, T. Taubner, and R. Hillenbrand, “Nanoscale resolved infrared probing of crystal structure and of plasmon-phonon coupling,” Nano Lett. 6(4), 774–778 (2006).
[Crossref] [PubMed]

N. Ocelic, A. Huber, and R. Hillenbrand, “Pseudoheterodyne detection for background-free near-field spectroscopy,” Appl. Phys. Lett. 89(10), 101124 (2006).
[Crossref]

Huber, A. J.

A. J. Huber, J. Wittborn, and R. Hillenbrand, “Infrared spectroscopic near-field mapping of single nanotransistors,” Nanotechnology 21(23), 235702 (2010).
[Crossref] [PubMed]

A. J. Huber, A. Ziegler, T. Köck, and R. Hillenbrand, “Infrared nanoscopy of strained semiconductors,” Nat. Nanotechnol. 4(3), 153–157 (2009).
[Crossref] [PubMed]

A. M. Gigler, A. J. Huber, M. Bauer, A. Ziegler, R. Hillenbrand, and R. W. Stark, “Nanoscale residual stress-field mappingaround nanoindents in SiCby IR s-SNOM and confocal Raman microscopy,” Opt. Express 17(25), 22351–22357 (2009).
[Crossref] [PubMed]

A. J. Huber, D. Kazantsev, F. Keilmann, J. Wittborn, and R. Hillenbrand, “Simultaneous IR material recognition and conductivity mapping by nanoscale near-field microscopy,” Adv. Mater. 19(17), 2209–2212 (2007).
[Crossref]

Huth, F.

P. Hermann, A. Hoehl, P. Patoka, F. Huth, E. Rühl, and G. Ulm, “Near-field imaging and nano-Fourier-transform infrared spectroscopy using broadband synchrotron radiation,” Opt. Express 21(3), 2913–2919 (2013).
[Crossref] [PubMed]

F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
[Crossref] [PubMed]

F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, “Infrared-spectroscopic nanoimaging with a thermal source,” Nat. Mater. 10(5), 352–356 (2011).
[Crossref] [PubMed]

Ilegems, M.

A. S. Barker and M. Ilegems, “Infrared lattice vibrations and free-electron dispersion in GaN,” Phys. Rev. B 7(2), 743–750 (1973).
[Crossref]

Jiang, D. S.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Josberger, E. E.

Jungbluth, B.

J. Wueppen, B. Jungbluth, T. Taubner, and P. Loosen, “Ultrafast tunable mid IR source,” in Proceedings of IEEE IRMMW-THz (Houston, TX, 2011).

Kachi, T.

T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
[Crossref]

Kalisch, H.

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

Kano, H.

T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
[Crossref]

Kazantsev, D.

A. J. Huber, D. Kazantsev, F. Keilmann, J. Wittborn, and R. Hillenbrand, “Simultaneous IR material recognition and conductivity mapping by nanoscale near-field microscopy,” Adv. Mater. 19(17), 2209–2212 (2007).
[Crossref]

Kehr, S. C.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

Keilmann, F.

F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
[Crossref] [PubMed]

S. Amarie and F. Keilmann, “Broadband-infrared assessment of phonon resonance in scattering-type near-field microscopy,” Phys. Rev. B 83(4), 045404 (2011).
[Crossref]

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

A. J. Huber, D. Kazantsev, F. Keilmann, J. Wittborn, and R. Hillenbrand, “Simultaneous IR material recognition and conductivity mapping by nanoscale near-field microscopy,” Adv. Mater. 19(17), 2209–2212 (2007).
[Crossref]

M. Brehm, T. Taubner, R. Hillenbrand, and F. Keilmann, “Infrared spectroscopic mapping of single nanoparticles and viruses at nanoscale resolution,” Nano Lett. 6(7), 1307–1310 (2006).
[Crossref] [PubMed]

T. Taubner, R. Hillenbrand, and F. Keilmann, “Nanoscale polymer recognition by spectral signature in scattering infrared near-field microscopy,” Appl. Phys. Lett. 85(21), 5064–5066 (2004).
[Crossref]

T. Taubner, R. Hillenbrand, and F. Keilmann, “Performance of visible and mid-infrared scattering-type near-field optical microscopes,” J. Microsc. 210(3), 311–314 (2003).
[Crossref] [PubMed]

R. Hillenbrand, T. Taubner, and F. Keilmann, “Phonon-enhanced light matter interaction at the nanometre scale,” Nature 418(6894), 159–162 (2002).
[Crossref] [PubMed]

Ketteniss, N.

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

Kim, C.

C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
[Crossref]

Kim, K.

C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
[Crossref]

Köck, T.

A. J. Huber, A. Ziegler, T. Köck, and R. Hillenbrand, “Infrared nanoscopy of strained semiconductors,” Nat. Nanotechnol. 4(3), 153–157 (2009).
[Crossref] [PubMed]

Koide, N.

T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
[Crossref]

Kozawa, T.

T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
[Crossref]

Kub, F.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Kuball, M.

M. Kuball, “Raman spectroscopy of GaN, AlGaN and AlN for process and growth monitoring/control,” Surf. Interface Anal. 31(10), 987–999 (2001).
[Crossref]

Lau, C. N.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Lea, A. S.

Lin, L.

Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
[Crossref] [PubMed]

Liu, Z. S.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Lockwood, D. J.

G. Yu, N. L. Rowell, and D. J. Lockwood, “Anisotropic infrared optical properties of GaN and sapphire,” J. Vac. Sci. Technol. A 22(4), 1110–1114 (2004).
[Crossref]

Loosen, P.

J. Wueppen, B. Jungbluth, T. Taubner, and P. Loosen, “Ultrafast tunable mid IR source,” in Proceedings of IEEE IRMMW-THz (Houston, TX, 2011).

Manabe, K.

T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
[Crossref]

Mastro, M. A.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Meyer, J. R.

I. Vurgaftman and J. R. Meyer, “Band paramters for nitrogen-containing semiconductors,” J. Appl. Phys. 94(6), 3675–3696 (2003).
[Crossref]

Mieth, O.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

Monteiro, T.

R. Seitz, T. Monteiro, E. Pereira, and M. Di Forte-Poisson, “Strain relaxation in GaN films as a function of growth direction and buffer layer measured by Raman spectroscopy,” Phys. Status Solidi, A Appl. Res. 176(1), 661–664 (1999).
[Crossref]

Myoung, J.

C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
[Crossref]

Nagase, H.

T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
[Crossref]

Neudeck, P. G.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Ni, J. Y.

J. S. Xue, Y. Hao, J. C. Zhang, and J. Y. Ni, “Comparative study of different properties of GaN films grown on (0001) sapphire using high and low temperature AlN interlayers,” Chin. Phys. B 19(5), 057203 (2010).
[Crossref]

Nuansing, W.

F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
[Crossref] [PubMed]

Ocelic, N.

F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, “Infrared-spectroscopic nanoimaging with a thermal source,” Nat. Mater. 10(5), 352–356 (2011).
[Crossref] [PubMed]

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Material-specific infrared recognition of single sub-10 nm particles by substrate-enhanced scattering-type near-field microscopy,” Nano Lett. 7(10), 3177–3181 (2007).
[Crossref] [PubMed]

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Analytical model for quantitative prediction of material contrasts in scattering-type near-field optical microscopy,” Opt. Express 15(14), 8550–8565 (2007).
[Crossref] [PubMed]

A. Huber, N. Ocelic, T. Taubner, and R. Hillenbrand, “Nanoscale resolved infrared probing of crystal structure and of plasmon-phonon coupling,” Nano Lett. 6(4), 774–778 (2006).
[Crossref] [PubMed]

N. Ocelic, A. Huber, and R. Hillenbrand, “Pseudoheterodyne detection for background-free near-field spectroscopy,” Appl. Phys. Lett. 89(10), 101124 (2006).
[Crossref]

N. Ocelic and R. Hillenbrand, “Subwavelength-scale tailoring of surface phonon polaritons by focused ion-beam implantation,” Nat. Mater. 3(9), 606–609 (2004).
[Crossref] [PubMed]

Patoka, P.

Pereira, E.

R. Seitz, T. Monteiro, E. Pereira, and M. Di Forte-Poisson, “Strain relaxation in GaN films as a function of growth direction and buffer layer measured by Raman spectroscopy,” Phys. Status Solidi, A Appl. Res. 176(1), 661–664 (1999).
[Crossref]

Phillips, M. C.

Powell, J. A.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Qiu, Y. X.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Rang, M.

X. G. Xu, M. Rang, I. M. Craig, and M. B. Raschke, “Pushing the sample-size limit of infrared vibrational nanospectroscopy: from monolayer toward single molecule sensitivity,” J. Phys. Chem. Lett. 3(13), 1836–1841 (2012).
[Crossref]

Raschke, M. B.

I. M. Craig, M. S. Taubman, A. S. Lea, M. C. Phillips, E. E. Josberger, and M. B. Raschke, “Infrared near-field spectroscopy of trace explosives using an external cavity quantum cascade laser,” Opt. Express 21(25), 30401–30414 (2013).
[Crossref] [PubMed]

X. G. Xu, M. Rang, I. M. Craig, and M. B. Raschke, “Pushing the sample-size limit of infrared vibrational nanospectroscopy: from monolayer toward single molecule sensitivity,” J. Phys. Chem. Lett. 3(13), 1836–1841 (2012).
[Crossref]

Renucci, M. A.

F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
[Crossref]

Reuters, B.

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

Robinson, I. K.

C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
[Crossref]

Rowell, N. L.

G. Yu, N. L. Rowell, and D. J. Lockwood, “Anisotropic infrared optical properties of GaN and sapphire,” J. Vac. Sci. Technol. A 22(4), 1110–1114 (2004).
[Crossref]

Rühl, E.

S McLeod, A.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Schneider, S.

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

Schnell, M.

F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, “Infrared-spectroscopic nanoimaging with a thermal source,” Nat. Mater. 10(5), 352–356 (2011).
[Crossref] [PubMed]

Seidel, J.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

Seitz, R.

R. Seitz, T. Monteiro, E. Pereira, and M. Di Forte-Poisson, “Strain relaxation in GaN films as a function of growth direction and buffer layer measured by Raman spectroscopy,” Phys. Status Solidi, A Appl. Res. 176(1), 661–664 (1999).
[Crossref]

Shim, K.

C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
[Crossref]

Speck, J. S.

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

Stark, R. W.

Stehr, D.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

Stewart, M. K.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Tauber, M. J.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Taubman, M. S.

Taubner, T.

J. M. Hoffmann, B. Hauer, and T. Taubner, “Antenna-enhanced infrared near-field nanospectroscopy of a polymer,” Appl. Phys. Lett. 101(19), 193105 (2012).
[Crossref]

M. Brehm, T. Taubner, R. Hillenbrand, and F. Keilmann, “Infrared spectroscopic mapping of single nanoparticles and viruses at nanoscale resolution,” Nano Lett. 6(7), 1307–1310 (2006).
[Crossref] [PubMed]

A. Huber, N. Ocelic, T. Taubner, and R. Hillenbrand, “Nanoscale resolved infrared probing of crystal structure and of plasmon-phonon coupling,” Nano Lett. 6(4), 774–778 (2006).
[Crossref] [PubMed]

T. Taubner, R. Hillenbrand, and F. Keilmann, “Nanoscale polymer recognition by spectral signature in scattering infrared near-field microscopy,” Appl. Phys. Lett. 85(21), 5064–5066 (2004).
[Crossref]

T. Taubner, R. Hillenbrand, and F. Keilmann, “Performance of visible and mid-infrared scattering-type near-field optical microscopes,” J. Microsc. 210(3), 311–314 (2003).
[Crossref] [PubMed]

R. Hillenbrand, T. Taubner, and F. Keilmann, “Phonon-enhanced light matter interaction at the nanometre scale,” Nature 418(6894), 159–162 (2002).
[Crossref] [PubMed]

J. Wueppen, B. Jungbluth, T. Taubner, and P. Loosen, “Ultrafast tunable mid IR source,” in Proceedings of IEEE IRMMW-THz (Houston, TX, 2011).

Thiemens, M.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Trunek, A. J.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Twigg, M. E.

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

Ulm, G.

Vescan, A.

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

Vurgaftman, I.

I. Vurgaftman and J. R. Meyer, “Band paramters for nitrogen-containing semiconductors,” J. Appl. Phys. 94(6), 3675–3696 (2003).
[Crossref]

Wagner, J. M.

J. M. Wagner and F. Bechstedt, “Properties of strained wurtzite GaN and AlN: Ab initio studies,” Phys. Rev. B 66(11), 115202 (2002).
[Crossref]

Wang, C.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Wang, H.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Wang, Y. T.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Wang, Z. L.

Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
[Crossref] [PubMed]

Watson, I. M.

I. M. Watson, “Metal organic vapour phase epitaxy of AlN, GaN, InN and their alloys: A key chemical technology for advanced device applications,” Coord. Chem. Rev. 257(13-14), 2120–2141 (2013).
[Crossref]

Wille, A.

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

Winnerl, S.

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

Wittborn, J.

F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, “Infrared-spectroscopic nanoimaging with a thermal source,” Nat. Mater. 10(5), 352–356 (2011).
[Crossref] [PubMed]

A. J. Huber, J. Wittborn, and R. Hillenbrand, “Infrared spectroscopic near-field mapping of single nanotransistors,” Nanotechnology 21(23), 235702 (2010).
[Crossref] [PubMed]

A. J. Huber, D. Kazantsev, F. Keilmann, J. Wittborn, and R. Hillenbrand, “Simultaneous IR material recognition and conductivity mapping by nanoscale near-field microscopy,” Adv. Mater. 19(17), 2209–2212 (2007).
[Crossref]

Wueppen, J.

J. Wueppen, B. Jungbluth, T. Taubner, and P. Loosen, “Ultrafast tunable mid IR source,” in Proceedings of IEEE IRMMW-THz (Houston, TX, 2011).

Xu, K.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Xu, X. G.

X. G. Xu, M. Rang, I. M. Craig, and M. B. Raschke, “Pushing the sample-size limit of infrared vibrational nanospectroscopy: from monolayer toward single molecule sensitivity,” J. Phys. Chem. Lett. 3(13), 1836–1841 (2012).
[Crossref]

Xue, J. S.

J. S. Xue, Y. Hao, J. C. Zhang, and J. Y. Ni, “Comparative study of different properties of GaN films grown on (0001) sapphire using high and low temperature AlN interlayers,” Chin. Phys. B 19(5), 057203 (2010).
[Crossref]

Yang, H.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Yang, J. R.

S. Y. Huang and J. R. Yang, “A transmission electron microscopy observation of dislocations in GaN grown on (0001) sapphire by metal organic chemical vapor deposition,” Jpn. J. Appl. Phys. 47(10), 7998–8002 (2008).
[Crossref]

Yoo, M. C.

C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
[Crossref]

Yu, G.

G. Yu, N. L. Rowell, and D. J. Lockwood, “Anisotropic infrared optical properties of GaN and sapphire,” J. Vac. Sci. Technol. A 22(4), 1110–1114 (2004).
[Crossref]

Zhang, J. C.

J. S. Xue, Y. Hao, J. C. Zhang, and J. Y. Ni, “Comparative study of different properties of GaN films grown on (0001) sapphire using high and low temperature AlN interlayers,” Chin. Phys. B 19(5), 057203 (2010).
[Crossref]

Zhang, L. M.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Zhang, S. M.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Zhang, Y.

Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
[Crossref] [PubMed]

Zhao, D. G.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Zhao, Z.

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Zhu, G.

Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
[Crossref] [PubMed]

Zhu, J. J.

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Ziegler, A.

Adv. Mater. (1)

A. J. Huber, D. Kazantsev, F. Keilmann, J. Wittborn, and R. Hillenbrand, “Simultaneous IR material recognition and conductivity mapping by nanoscale near-field microscopy,” Adv. Mater. 19(17), 2209–2212 (2007).
[Crossref]

Appl. Phys. Lett. (7)

T. Taubner, R. Hillenbrand, and F. Keilmann, “Nanoscale polymer recognition by spectral signature in scattering infrared near-field microscopy,” Appl. Phys. Lett. 85(21), 5064–5066 (2004).
[Crossref]

J. M. Hoffmann, B. Hauer, and T. Taubner, “Antenna-enhanced infrared near-field nanospectroscopy of a polymer,” Appl. Phys. Lett. 101(19), 193105 (2012).
[Crossref]

J. D. Caldwell, M. A. Mastro, K. D. Hobart, O. J. Glembocki, C. R. Eddy, N. D. Bassim, R. T. Holm, R. L. Henry, M. E. Twigg, F. Kub, P. G. Neudeck, A. J. Trunek, and J. A. Powell, “Improved ultraviolet emission from reduced defect gallium nitride homojunctions grown on step-free 4H-SiC mesas,” Appl. Phys. Lett. 88(26), 263509 (2006).
[Crossref]

S. Schneider, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Impact of optical in-plane anisotropy on near-field phonon polariton spectroscopy,” Appl. Phys. Lett. 90(14), 143101 (2007).
[Crossref]

N. Ocelic, A. Huber, and R. Hillenbrand, “Pseudoheterodyne detection for background-free near-field spectroscopy,” Appl. Phys. Lett. 89(10), 101124 (2006).
[Crossref]

C. Kim, I. K. Robinson, J. Myoung, K. Shim, M. C. Yoo, and K. Kim, “Critical thickness of GaN thin films on sapphire (0001),” Appl. Phys. Lett. 69(16), 2358–2360 (1996).
[Crossref]

T. Böttcher, S. Einfeldt, S. Figge, R. Chierchia, H. Heinke, D. Hommel, and J. S. Speck, “The role of high-temperature island coalescence in the development of stresses in GaN films,” Appl. Phys. Lett. 78(14), 1976–1978 (2001).
[Crossref]

Chin. Phys. B (2)

J. S. Xue, Y. Hao, J. C. Zhang, and J. Y. Ni, “Comparative study of different properties of GaN films grown on (0001) sapphire using high and low temperature AlN interlayers,” Chin. Phys. B 19(5), 057203 (2010).
[Crossref]

X. Guo, Y. T. Wang, D. G. Zhao, D. S. Jiang, J. J. Zhu, Z. S. Liu, H. Wang, S. M. Zhang, Y. X. Qiu, K. Xu, and H. Yang, “Microstructure and strain analysis of GaN epitaxial films using in-plane grazing incidence X-ray diffraction,” Chin. Phys. B 19(7), 076804 (2010).
[Crossref]

Coord. Chem. Rev. (1)

I. M. Watson, “Metal organic vapour phase epitaxy of AlN, GaN, InN and their alloys: A key chemical technology for advanced device applications,” Coord. Chem. Rev. 257(13-14), 2120–2141 (2013).
[Crossref]

J. Appl. Phys. (2)

I. Vurgaftman and J. R. Meyer, “Band paramters for nitrogen-containing semiconductors,” J. Appl. Phys. 94(6), 3675–3696 (2003).
[Crossref]

T. Kozawa, T. Kachi, H. Kano, H. Nagase, N. Koide, and K. Manabe, “Thermal stress in GaN epitaxial layers grown on sapphire substrates,” J. Appl. Phys. 77(9), 4389–4392 (1995).
[Crossref]

J. Electron. Mater. (1)

B. Reuters, A. Wille, N. Ketteniss, H. Hahn, B. Holländer, M. Heuken, H. Kalisch, and A. Vescan, “Polarization engineered enhancement-mode high-electron-mobility transistors using quaternary AlInGaN barrier layers,” J. Electron. Mater. 42(5), 826–832 (2013).
[Crossref]

J. Microsc. (1)

T. Taubner, R. Hillenbrand, and F. Keilmann, “Performance of visible and mid-infrared scattering-type near-field optical microscopes,” J. Microsc. 210(3), 311–314 (2003).
[Crossref] [PubMed]

J. Phys. Chem. Lett. (1)

X. G. Xu, M. Rang, I. M. Craig, and M. B. Raschke, “Pushing the sample-size limit of infrared vibrational nanospectroscopy: from monolayer toward single molecule sensitivity,” J. Phys. Chem. Lett. 3(13), 1836–1841 (2012).
[Crossref]

J. Vac. Sci. Technol. A (1)

G. Yu, N. L. Rowell, and D. J. Lockwood, “Anisotropic infrared optical properties of GaN and sapphire,” J. Vac. Sci. Technol. A 22(4), 1110–1114 (2004).
[Crossref]

Jpn. J. Appl. Phys. (1)

S. Y. Huang and J. R. Yang, “A transmission electron microscopy observation of dislocations in GaN grown on (0001) sapphire by metal organic chemical vapor deposition,” Jpn. J. Appl. Phys. 47(10), 7998–8002 (2008).
[Crossref]

Nano Lett. (6)

Z. Fei, G. O. Andreev, W. Bao, L. M. Zhang, A. S McLeod, C. Wang, M. K. Stewart, Z. Zhao, G. Dominguez, M. Thiemens, M. M. Fogler, M. J. Tauber, A. H. Castro-Neto, C. N. Lau, F. Keilmann, and D. N. Basov, “Infrared nanoscopy of Dirac plasmons at the graphene-SiO₂ interface,” Nano Lett. 11(11), 4701–4705 (2011).
[Crossref] [PubMed]

Y. Hu, Y. Zhang, L. Lin, Y. Ding, G. Zhu, and Z. L. Wang, “Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films,” Nano Lett. 12(7), 3851–3856 (2012).
[Crossref] [PubMed]

M. Brehm, T. Taubner, R. Hillenbrand, and F. Keilmann, “Infrared spectroscopic mapping of single nanoparticles and viruses at nanoscale resolution,” Nano Lett. 6(7), 1307–1310 (2006).
[Crossref] [PubMed]

A. Cvitkovic, N. Ocelic, and R. Hillenbrand, “Material-specific infrared recognition of single sub-10 nm particles by substrate-enhanced scattering-type near-field microscopy,” Nano Lett. 7(10), 3177–3181 (2007).
[Crossref] [PubMed]

A. Huber, N. Ocelic, T. Taubner, and R. Hillenbrand, “Nanoscale resolved infrared probing of crystal structure and of plasmon-phonon coupling,” Nano Lett. 6(4), 774–778 (2006).
[Crossref] [PubMed]

F. Huth, A. Govyadinov, S. Amarie, W. Nuansing, F. Keilmann, and R. Hillenbrand, “Nano-FTIR absorption spectroscopy of molecular fingerprints at 20 nm spatial resolution,” Nano Lett. 12(8), 3973–3978 (2012).
[Crossref] [PubMed]

Nanotechnology (1)

A. J. Huber, J. Wittborn, and R. Hillenbrand, “Infrared spectroscopic near-field mapping of single nanotransistors,” Nanotechnology 21(23), 235702 (2010).
[Crossref] [PubMed]

Nat. Mater. (2)

N. Ocelic and R. Hillenbrand, “Subwavelength-scale tailoring of surface phonon polaritons by focused ion-beam implantation,” Nat. Mater. 3(9), 606–609 (2004).
[Crossref] [PubMed]

F. Huth, M. Schnell, J. Wittborn, N. Ocelic, and R. Hillenbrand, “Infrared-spectroscopic nanoimaging with a thermal source,” Nat. Mater. 10(5), 352–356 (2011).
[Crossref] [PubMed]

Nat. Nanotechnol. (1)

A. J. Huber, A. Ziegler, T. Köck, and R. Hillenbrand, “Infrared nanoscopy of strained semiconductors,” Nat. Nanotechnol. 4(3), 153–157 (2009).
[Crossref] [PubMed]

Nature (1)

R. Hillenbrand, T. Taubner, and F. Keilmann, “Phonon-enhanced light matter interaction at the nanometre scale,” Nature 418(6894), 159–162 (2002).
[Crossref] [PubMed]

Opt. Express (4)

Phys. Rev. B (3)

J. M. Wagner and F. Bechstedt, “Properties of strained wurtzite GaN and AlN: Ab initio studies,” Phys. Rev. B 66(11), 115202 (2002).
[Crossref]

A. S. Barker and M. Ilegems, “Infrared lattice vibrations and free-electron dispersion in GaN,” Phys. Rev. B 7(2), 743–750 (1973).
[Crossref]

S. Amarie and F. Keilmann, “Broadband-infrared assessment of phonon resonance in scattering-type near-field microscopy,” Phys. Rev. B 83(4), 045404 (2011).
[Crossref]

Phys. Rev. Lett. (1)

S. C. Kehr, M. Cebula, O. Mieth, T. Härtling, J. Seidel, S. Grafström, L. M. Eng, S. Winnerl, D. Stehr, and M. Helm, “Anisotropy contrast in phonon-enhanced apertureless near-field microscopy using a free-electron laser,” Phys. Rev. Lett. 100(25), 256403 (2008).
[Crossref] [PubMed]

Phys. Status Solidi, A Appl. Res. (1)

R. Seitz, T. Monteiro, E. Pereira, and M. Di Forte-Poisson, “Strain relaxation in GaN films as a function of growth direction and buffer layer measured by Raman spectroscopy,” Phys. Status Solidi, A Appl. Res. 176(1), 661–664 (1999).
[Crossref]

Solid State Commun. (1)

F. Demangeot, J. Frandon, M. A. Renucci, O. Briot, B. Gil, and R. L. Aulombard, “Raman determination of phonon deformation potentials in alpha-GaN,” Solid State Commun. 100(4), 207–210 (1996).
[Crossref]

Surf. Interface Anal. (1)

M. Kuball, “Raman spectroscopy of GaN, AlGaN and AlN for process and growth monitoring/control,” Surf. Interface Anal. 31(10), 987–999 (2001).
[Crossref]

Other (3)

F. Keilmann and R. Hillenbrand, “Near-field nanoscopy by elastic light scattering from a tip,” in A. Zayats and D. Richards, eds., Nano-Optics and Near-Field Optical Microscopy (Artech House, 2009), Chap. 11, pp. 235–265.

N. Ocelic, “Quantitative near-field phonon-polariton spectroscopy,” Dissertation, TU München, 2007.

J. Wueppen, B. Jungbluth, T. Taubner, and P. Loosen, “Ultrafast tunable mid IR source,” in Proceedings of IEEE IRMMW-THz (Houston, TX, 2011).

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Figures (5)

Fig. 1
Fig. 1 Broadband SNOM. (a) Spectral range of different laser systems successfully used for SNOM experiments. See literature [12,16,23] for further details; part of the data were taken from the web pages of the companies Edinburgh Instruments, Block Engineering and Daylight Solutions. (b) Calculated SNOM amplitude spectra for various phonon resonant materials normalized on gold. (c) Examples of laser spectra of the ILT broadband laser used in this paper. The central wavelength is continuously tunable between 9 µm and 16 µm, with spectral widths (FWHM) from approx. 40 cm−1 to 130 cm−1. Note that these widths are matched very well to those of the phonon-resonances. (d) Experimental setup of the broadband SNOM.
Fig. 2
Fig. 2 Indent in GaN layer. (a) Topography and (b) interferometrically recorded 2D optical near-field image (second harmonic amplitude) of the indent. See text and Fig. 3 for more details about this measurement method. The shape of the indent is clearly visible. It is surrounded by brighter and darker areas denoting different stress levels in the crystal structure. (c) Sketch of the sample. (d) Near-field spectra of GaN, normalized to gold, measured at different positions on the sample: A and B are close to one of the indents as marked in 2(b). Position C is further away from the indent where the sample is expected to be unaffected by the indentation. The spectra are evaluated by a fit which is shown as solid line.
Fig. 3
Fig. 3 2D imaging of stress in a GaN layer. (a) and (b) show the second harmonic amplitude of the interferograms that correspond to the spectra in Fig. 2(d) and to the positions marked in (c). The interferograms differ from one another which leads to an optical contrast between differently stressed crystal areas as illustrated with the black. (c)-(e) show the optical amplitudes (second harmonic) for different positions of the end mirror in the interferometer arm that are marked in 3(b) (dashed lines). The color scale is the same as in (e) for all three images. In (c) and (e), a hexagonal pattern is visible that reveals the differently strained areas on the sample.
Fig. 4
Fig. 4 (a) Sketch of the second sample. The cross section sample is tilted 90° compared to the indent sample. The spectra are taken on the GaN layer with different distances from the AlN layer. (b) illustrates schematically the lattice mismatch between GaN and AlN that leads to strain in the crystal lattice.
Fig. 5
Fig. 5 Cross section of a layered sapphire/AlN/GaN structure. (a) Sketch of the sample structure. (b) Topography of the sample and (c) the corresponding second harmonic optical amplitude signal. The bright area next to GaN is from the covering. Across the GaN layer, several spectra are recorded that are shown in (d). The solid lines are fits to the data. (e) shows the relative differences in stress levels calculated from the shift in the LO phonon frequencies ωLO. Note that the value of 0 GPa at a GaN thickness of 0.6 µm is set arbitrarily. The damping constants Γ are plotted in (f).

Equations (1)

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ε ( ω ) = ε + ε ( ω LO 2 ω TO 2 ) ω TO 2 ω 2 i ω Γ + ω p 2 ω 2 i ω γ

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