Abstract

The extraction efficiency of nonpolar a-plane (11-20) GaN LEDs on sapphire substrates has been enhanced by selectively etching the mesa sidewall faces and the n-type GaN surfaces with photoenhanced chemical wet etching. Submicron-sized trigonal prisms having prismatic planes of {1-100} were clearly displayed on the n-type GaN surfaces as well as the sidewall face after 5 min etching at 60°C. The radiation patterns have shown that more light is extracted in all directions and the output powers of surface textured a-plane GaN LEDs have increased by 25% compared with control samples. PEC wet etching produced unique feature of etching morphology on the mesa sidewall faces and the n-type GaN surface.

© 2010 OSA

1. Introduction

Nitride-based light-emitting diodes (LEDs) on nonpolar orientations have received increasing attention over the past several years due to their promise of removing the quantum-confined Stark effect. The polarization-related electric field induces electron and hole wavefunctions to be spatially separated in strained quantum well (QW) structure, leading to a reduced optical transition probability [13]. The absence of internal electric field in nonpolar gallium nitride (GaN) LEDs is advantageous to achieve not only highly-efficient light emitters with thicker QWs, but also improved wavelength stability with injection currents. Many research groups have successfully demonstrated nonpolar a-plane (11-20) and m-plane (1100) GaN LEDs as well as semipolar (10-1-1) and (11-22) GaN LEDs [412]. Masui et al. had recently reported comprehensive review on achievements and challenges on nonpolar and semipolar nitride LEDs [13].

There have been intensive efforts to increase the extraction efficiency in GaN LEDs to improve the external quantum efficiency. It is well known that a significant fraction of generated lights are trapped inside the cavity due to total internal reflection. Thus, a variety of extraction methods are currently employed such as highly reflective p-electrode, chip geometry deformation, patterned sapphire substrate, photonic crystals, and surface roughening. Since Minsky et al. had demonstrated photoenhanced chemical (PEC) wet etching on GaN, the surface texturing with hexagonal pyramidal structures on chemically active nitrogen-face GaN is now commonly used in vertical thin-film GaN LEDs due to its simple and damage-free etching process [14,15]. It is obvious that PEC wet etching can be also implemented in nonpolar and semipolar GaN films by selectively etching different crystallographic planes [1618]. Hardy et al. recently demonstrated a nonpolar m-plane superluminescent diode by forming hexagonal pyramids on –c (000-1) face via PEC etching [19]. However, there are few reports available on PEC wet etching on heteroepitaxial a-plane GaN LEDs. In this work, we investigated how selective wet etching changes the morphology of a-plane GaN surfaces as well as mesa sidewall faces in nonpolar a-plane GaN LEDs on r-plane sapphire substrates.

2. Experimental details

High crystalline a-plane (11-20) GaN film was directly grown on r-plane (1-102) sapphire substrates by metalorganic chemical vapor deposition, utilizing a two-step growth method with high-temperature GaN buffer. Nonpolar a-plane InGaN/ GaN LEDs were subsequently grown on 4.5 μm thick a-plane GaN films. The doping concentration of the Si-doped n-GaN layer was 3 × 1018 cm−3, and four periods of 5 nm thick InGaN QW layer and 9 nm thick GaN barrier layer were grown for the active region, followed by 150 nm thick Mg-doped p-GaN layer with doping of 1.4 × 1018 cm−3. For a p-electrode, Ni/Au (3 nm/3 nm) was deposited on the p-GaN layer using an e-beam evaporator, followed by annealing in air ambient to form Ohmic contacts. The mesa pattern with dimension of 200 μm × 500 μm was transferred into the n-GaN layer down to 1 μm by inductively coupled plasma etching. Cr/Au (50 nm/400 nm) was deposited as the n-electrode.

A schematic diagram of heteroepitaxial a-plane InGaN/GaN LED structure is presented in Fig. 1(A) . Note that our a-plane non-polar InGaN/GaN LED devices are aligned with c-axis [Fig. 1(B) and 1(C)]. Figure 1(C) is a plan-view optical microscope image of LED chip. Fabricated LED devices were then immersed in a potassium hydroxide (KOH) solution for different periods of time. PEC etchings were performed at stirring rate of 300 rpm at 60°C with ultraviolet illuminations. Electrical and optical properties of LEDs were characterized by an on-wafer measurement system.

 

Fig. 1 (A). Schematic diagram of heteroepitaxial a-plane InGaN/GaN LED structure (B). Schematic diagram of GaN planes showing c-axis, c-plane and a-plane. (C) Microscope image of the processed a-plane InGaN/GaN LED.

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3. Results and discussion

Plan-view scanning electron microscope (SEM) images of the mesa sidewall face in the + c-axis [0001] direction are shown Fig. 2(A) before and Fig. 2(B) after KOH etching in KOH solution. Figure 2(B) shows a clear evidence of PEC etching on the mesa sidewall in the + c-axis direction. A bundle of trigonal prisms having various widths from hundreds of nanometer to 1 micron were observed. These submicron-sized trigonal prisms with prismatic planes of {1-100} also indicate that the normal plane is a-plane (11-20). It is notable that the p-GaN layer was roughened in this case with relatively low temperature, and the p-GaN layer was intact after PEC etching due to Ni/Au contact layer.

 

Fig. 2 SEM images in the direction of + c-axis [0001] of the mesa sidewall of LED samples (A) before and (B) after 5 min etching.

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Figure 3(A) , 3(B), and 3(C) show SEM images of the sidewall faces after 5 min etching in the direction of the + c-axis, the + m-axis [1-100], and the –c-axis [000-1], respectively. The sidewall face in the + m-axis direction turned into rough surface morphology, which was the same case for the sidewall face in the –m-axis direction. Figure 3(C) is the sidewall face in the –c-axis direction, showing different surface morphology with the one in the + c-axis direction. There appeared a specific crystallographic plane as an etch-stop plane at the bottom of the sidewall, which was previously reported to be (−1-12-2) plane [20]. Typical cone-shaped morphology can be seen on top of the sidewall in the –c-axis direction. It is important to note that the surface of n-type GaN between mesa sidewalls and n-contact is also textured simultaneously, showing a high density of trigonal prisms with a few hundred nanometer scale aligned along the + c-axis. As can be seen Fig. 2 and 3, PEC wet etching produced unique feature of etching morphology on the mesa sidewall faces and the n-type GaN surface, which is beneficial to increase the light extraction efficiency of a-plane GaN LEDs.

 

Fig. 3 SEM images of PEC textured LED samples in the directions of (A) + c-axis [0001], (B) + m-direction [1-100], and (C) –c-axis [000-1].

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In order to investigate the effects of PEC wet etching, the output powers of etched LED samples were measured at the current injection of 20mA from on-wafer measurements (Fig. 4 ). The light output powers of 5 min etched LEDs were 25% higher in average than those of control samples. The increase of output power can be attributed to the roughened n-type GaN surface as well as the sidewall faces. As shown in Fig. 5 , the radiation patterns confirm that more lights are extracted in all directions for the c-axis and m-axis rotations at 20 mA. PEC wet etching produces unique feature of etching morphology on the sidewall faces and the n-type GaN surfaces in a-plane GaN LEDs and significantly improves the extraction efficiency of heteroepitaxial a-plane GaN LEDs.

 

Fig. 4 The optical output powers of control and PEC textured LED samples for 5 min, measured on-wafer at the current injection of 20mA.

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Fig. 5 The comparison of radiation patterns of control and PEC textured a-plane LEDs, measured in m-axis and c-axis rotations.

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4. Conclusion

We report on the enhanced light extraction of heteroepitaxial a-plane GaN LEDs by selectively etching the sidewall faces and the n-type GaN surface via PEC wet etching. The light output powers of PEC etched LED samples have increased by 25% at 20mA current injection. The radiation patterns have also shown that lights are extracted at all directions, indicating that PEC wet etching is also quite effective to improve the extraction efficiency of heteroepitaxial a-plane GaN LEDs.

Acknowledgments

The work at Korea University was supported by the Carbon Dioxide Reduction and Sequestration Center, one of the 21st Century Frontier R&D Program funded by the Ministry of Education, Science and Technology of Korea. The work at KETI was supported by the IT R&D program (2009-F-022-01) and the International Joint R&D Program (10030797) by the Ministry of Knowledge Economy. Authors would like to thank Prof. J. I. Shim at Hanyang Univ. for measuring the radiation patterns.

References and links

1. F. Bernardini, V. Fiorentini, and D. Vanderbilt, “Spontaneous polarization and piezoelectric constants of III-V nitrides,” Phys. Rev. B 56(16), R10024–R10027 (1997). [CrossRef]  

2. J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998). [CrossRef]  

3. P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000). [CrossRef]   [PubMed]  

4. T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008). [CrossRef]  

5. S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009). [CrossRef]  

6. A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005). [CrossRef]  

7. M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006). [CrossRef]  

8. B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007). [CrossRef]  

9. M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007). [CrossRef]  

10. K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

11. Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009). [CrossRef]  

12. Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009). [CrossRef]  

13. H. Masui, S. Nakamura, S. P. DenBaars, and U. K. Mishra, “Nonpolar and Semipolar III-Nitride Light-Emitting Diodes: Achievements and Challenges,” IEEE Trans. Electron. Dev. 57(1), 88–100 (2010). [CrossRef]  

14. M. S. Minsky, M. White, and E. L. Hu, “Room‐temperature photoenhanced wet etching of GaN,” Appl. Phys. Lett. 68(11), 1531–1533 (1996). [CrossRef]  

15. T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004). [CrossRef]  

16. Y. Jung, M. Mastro, J. Hite, C. R. Eddy Jr, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010). [CrossRef]  

17. A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009). [CrossRef]  

18. A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009). [CrossRef]  

19. M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009). [CrossRef]  

20. Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004). [CrossRef]  

References

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  1. F. Bernardini, V. Fiorentini, and D. Vanderbilt, “Spontaneous polarization and piezoelectric constants of III-V nitrides,” Phys. Rev. B 56(16), R10024–R10027 (1997).
    [CrossRef]
  2. J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
    [CrossRef]
  3. P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
    [CrossRef] [PubMed]
  4. T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
    [CrossRef]
  5. S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
    [CrossRef]
  6. A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
    [CrossRef]
  7. M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
    [CrossRef]
  8. B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
    [CrossRef]
  9. M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
    [CrossRef]
  10. K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).
  11. Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
    [CrossRef]
  12. Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
    [CrossRef]
  13. H. Masui, S. Nakamura, S. P. DenBaars, and U. K. Mishra, “Nonpolar and Semipolar III-Nitride Light-Emitting Diodes: Achievements and Challenges,” IEEE Trans. Electron. Dev. 57(1), 88–100 (2010).
    [CrossRef]
  14. M. S. Minsky, M. White, and E. L. Hu, “Room‐temperature photoenhanced wet etching of GaN,” Appl. Phys. Lett. 68(11), 1531–1533 (1996).
    [CrossRef]
  15. T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
    [CrossRef]
  16. Y. Jung, M. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010).
    [CrossRef]
  17. A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009).
    [CrossRef]
  18. A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009).
    [CrossRef]
  19. M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
    [CrossRef]
  20. Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004).
    [CrossRef]

2010

H. Masui, S. Nakamura, S. P. DenBaars, and U. K. Mishra, “Nonpolar and Semipolar III-Nitride Light-Emitting Diodes: Achievements and Challenges,” IEEE Trans. Electron. Dev. 57(1), 88–100 (2010).
[CrossRef]

Y. Jung, M. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010).
[CrossRef]

2009

A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009).
[CrossRef]

A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009).
[CrossRef]

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

2008

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

2007

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

2006

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

2005

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

2004

Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004).
[CrossRef]

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

2000

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

1998

J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
[CrossRef]

1997

F. Bernardini, V. Fiorentini, and D. Vanderbilt, “Spontaneous polarization and piezoelectric constants of III-V nitrides,” Phys. Rev. B 56(16), R10024–R10027 (1997).
[CrossRef]

1996

M. S. Minsky, M. White, and E. L. Hu, “Room‐temperature photoenhanced wet etching of GaN,” Appl. Phys. Lett. 68(11), 1531–1533 (1996).
[CrossRef]

Baek, J. H.

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

Baik, K. H.

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

Bernardini, F.

F. Bernardini, V. Fiorentini, and D. Vanderbilt, “Spontaneous polarization and piezoelectric constants of III-V nitrides,” Phys. Rev. B 56(16), R10024–R10027 (1997).
[CrossRef]

Boyama, S.

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

Brandt, O.

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Brinkley, S.

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

Bruckner, P.

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

Chakraborty, A.

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

Cho, I.-S.

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

Cho, M.

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

Craven, M. D.

Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004).
[CrossRef]

Den Baars, S. P.

Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004).
[CrossRef]

DenBaars, S. P.

H. Masui, S. Nakamura, S. P. DenBaars, and U. K. Mishra, “Nonpolar and Semipolar III-Nitride Light-Emitting Diodes: Achievements and Challenges,” IEEE Trans. Electron. Dev. 57(1), 88–100 (2010).
[CrossRef]

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009).
[CrossRef]

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009).
[CrossRef]

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Detchprohm, T.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

Eddy, C. R.

Y. Jung, M. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010).
[CrossRef]

Fellows, N.

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

Feneberg, M.

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

Fiorentini, V.

F. Bernardini, V. Fiorentini, and D. Vanderbilt, “Spontaneous polarization and piezoelectric constants of III-V nitrides,” Phys. Rev. B 56(16), R10024–R10027 (1997).
[CrossRef]

Fujii, T.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Fujito, K.

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

Funato, M.

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

Gao, Y.

Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004).
[CrossRef]

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Grahn, H. T.

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Hangleiter, A.

J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
[CrossRef]

Hanser, D.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

Hardy, M. T.

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Haskell, B. A.

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

Hirai, A.

A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009).
[CrossRef]

A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009).
[CrossRef]

Hite, J.

Y. Jung, M. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010).
[CrossRef]

Hsu, P. S.

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Hu, E. L.

A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009).
[CrossRef]

A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009).
[CrossRef]

Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004).
[CrossRef]

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

M. S. Minsky, M. White, and E. L. Hu, “Room‐temperature photoenhanced wet etching of GaN,” Appl. Phys. Lett. 68(11), 1531–1533 (1996).
[CrossRef]

Hwang, S.-M.

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

Jung, S.

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

Jung, Y.

Y. Jung, M. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010).
[CrossRef]

Kawakami, Y.

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

Kelchner, K. M.

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Keller, S.

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

Kim, J.

Y. Jung, M. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010).
[CrossRef]

Kim, K.-C.

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

Kim, T. G.

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

Kollmer, H.

J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
[CrossRef]

Kosugi, T.

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

Kuo, H. C.

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

Li, Y.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

Lin, Y.-D.

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

Lipski, F.

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

Liu, L.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

Mastro, M.

Y. Jung, M. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010).
[CrossRef]

Masui, H.

H. Masui, S. Nakamura, S. P. DenBaars, and U. K. Mishra, “Nonpolar and Semipolar III-Nitride Light-Emitting Diodes: Achievements and Challenges,” IEEE Trans. Electron. Dev. 57(1), 88–100 (2010).
[CrossRef]

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

Melo, T.

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

Menniger, J.

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Minsky, M. S.

M. S. Minsky, M. White, and E. L. Hu, “Room‐temperature photoenhanced wet etching of GaN,” Appl. Phys. Lett. 68(11), 1531–1533 (1996).
[CrossRef]

Mishra, U. K.

H. Masui, S. Nakamura, S. P. DenBaars, and U. K. Mishra, “Nonpolar and Semipolar III-Nitride Light-Emitting Diodes: Achievements and Challenges,” IEEE Trans. Electron. Dev. 57(1), 88–100 (2010).
[CrossRef]

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

Mukai, T.

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

Nakada, N.

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

Nakamura, S.

H. Masui, S. Nakamura, S. P. DenBaars, and U. K. Mishra, “Nonpolar and Semipolar III-Nitride Light-Emitting Diodes: Achievements and Challenges,” IEEE Trans. Electron. Dev. 57(1), 88–100 (2010).
[CrossRef]

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009).
[CrossRef]

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Narukawa, Y.

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

Neubert, B.

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

Nitta, S.

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

Off, J.

J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
[CrossRef]

Ohta, H.

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Okuno, K.

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

Paskova, T.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

Ploog, K. H.

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Preble, E. A.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

Ramsteiner, M.

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Reiche, M.

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Saito, M.

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

Saito, Y.

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

Sato, H.

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

Schirra, M.

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

Schmidt, M.

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

Schmidt, M. C.

A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009).
[CrossRef]

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

Scholz, F.

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
[CrossRef]

Seo, Y. G.

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

Seo Im, J.

J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
[CrossRef]

Sharma, R.

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

Shibata, N.

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

Sohmer, A.

J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
[CrossRef]

Speck, J. S.

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004).
[CrossRef]

Takahashi, M.

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

Tamboli, A. C.

A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009).
[CrossRef]

A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009).
[CrossRef]

Thonke, K.

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

Trampert, A.

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Ueda, M.

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

Ushida, Y.

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

Vanderbilt, D.

F. Bernardini, V. Fiorentini, and D. Vanderbilt, “Spontaneous polarization and piezoelectric constants of III-V nitrides,” Phys. Rev. B 56(16), R10024–R10027 (1997).
[CrossRef]

Waltereit, P.

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Wetzel, C.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

White, M.

M. S. Minsky, M. White, and E. L. Hu, “Room‐temperature photoenhanced wet etching of GaN,” Appl. Phys. Lett. 68(11), 1531–1533 (1996).
[CrossRef]

Wu, F.

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

Wunderer, T.

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

Xia, Y.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

Zhu, M.

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

Appl. Phys. Express

Y. Saito, K. Okuno, S. Boyama, N. Nakada, S. Nitta, Y. Ushida, and N. Shibata, “m-Plane GaInN Light Emitting Diodes Grown on Patterned a-Plane Sapphire Substrates,” Appl. Phys. Express 2, 041001 (2009).
[CrossRef]

M. T. Hardy, K. M. Kelchner, Y.-D. Lin, P. S. Hsu, K. Fujito, H. Ohta, J. S. Speck, S. Nakamura, and S. P. DenBaars, “m-Plane GaN-Based Blue Superluminescent Diodes Fabricated Using Selective Chemical Wet Etching,” Appl. Phys. Express 2(12), 121004 (2009).
[CrossRef]

Appl. Phys. Lett.

Y. Gao, M. D. Craven, J. S. Speck, S. P. Den Baars, and E. L. Hu, “Dislocation- and crystallographic-dependent photoelectrochemical wet etching of gallium nitride,” Appl. Phys. Lett. 84(17), 3322–3324 (2004).
[CrossRef]

A. C. Tamboli, A. Hirai, S. Nakamura, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical etching of p-type GaN heterostructures,” Appl. Phys. Lett. 94(15), 151113 (2009).
[CrossRef]

Y.-D. Lin, A. Chakraborty, S. Brinkley, H. C. Kuo, T. Melo, K. Fujito, J. S. Speck, S. P. DenBaars, and S. Nakamura, “Characterization of blue-green m-plane InGaN light emitting diodes,” Appl. Phys. Lett. 94(26), 261108 (2009).
[CrossRef]

M. S. Minsky, M. White, and E. L. Hu, “Room‐temperature photoenhanced wet etching of GaN,” Appl. Phys. Lett. 68(11), 1531–1533 (1996).
[CrossRef]

T. Fujii, Y. Gao, R. Sharma, E. L. Hu, S. P. DenBaars, and S. Nakamura, “Increase in the extraction efficiency of GaN-based light-emitting diodes via surface roughening,” Appl. Phys. Lett. 84(6), 855–857 (2004).
[CrossRef]

T. Detchprohm, M. Zhu, Y. Li, Y. Xia, C. Wetzel, E. A. Preble, L. Liu, T. Paskova, and D. Hanser, “Green light emitting diodes on a-plane GaN bulk substrates,” Appl. Phys. Lett. 92(24), 241109 (2008).
[CrossRef]

S.-M. Hwang, Y. G. Seo, K. H. Baik, I.-S. Cho, J. H. Baek, S. Jung, T. G. Kim, and M. Cho, “Demonstration of nonpolar a-plane InGaN/GaN light emitting diode on r-plane sapphire substrate,” Appl. Phys. Lett. 95(7), 071101 (2009).
[CrossRef]

IEEE Trans. Electron. Dev.

H. Masui, S. Nakamura, S. P. DenBaars, and U. K. Mishra, “Nonpolar and Semipolar III-Nitride Light-Emitting Diodes: Achievements and Challenges,” IEEE Trans. Electron. Dev. 57(1), 88–100 (2010).
[CrossRef]

J. Cryst. Growth

B. Neubert, T. Wunderer, P. Bruckner, F. Scholz, M. Feneberg, F. Lipski, M. Schirra, and K. Thonke, “Semipolar GaN/GaInN LEDs with more than 1 mW optical output power,” J. Cryst. Growth 298, 706–709 (2007).
[CrossRef]

J. Electrochem. Soc.

A. C. Tamboli, M. C. Schmidt, A. Hirai, S. P. DenBaars, and E. L. Hu, “Photoelectrochemical undercut etching of m-plane GaN for microdisk applications,” J. Electrochem. Soc. 156(10), H767–H771 (2009).
[CrossRef]

Jpn. J. Appl. Phys.

M. Schmidt, K.-C. Kim, H. Sato, N. Fellows, H. Masui, S. Nakamura, S. P. DenBaars, and J. S. Speck, “High Power and High External Efficiency m-Plane InGaN Light Emitting Diodes,” Jpn. J. Appl. Phys. 46(7), L126–L128 (2007).
[CrossRef]

A. Chakraborty, B. A. Haskell, S. Keller, J. S. Speck, S. P. Denbaars, S. Nakamura, and U. K. Mishra, “Demonstration of Nonpolar m-Plane InGaN/GaN Light-Emitting Diodes on Free-Standing m-Plane GaN Substrates,” Jpn. J. Appl. Phys. 44(5), L173–L175 (2005).
[CrossRef]

M. Funato, M. Ueda, Y. Kawakami, Y. Narukawa, T. Kosugi, M. Takahashi, and T. Mukai, “Blue, Green, and Amber InGaN/GaN Light-Emitting Diodes on Semipolar {11-22} GaN Bulk Substrates,” Jpn. J. Appl. Phys. 45(26), L659–L662 (2006).
[CrossRef]

Nature

P. Waltereit, O. Brandt, A. Trampert, H. T. Grahn, J. Menniger, M. Ramsteiner, M. Reiche, and K. H. Ploog, “Nitride semiconductors free of electrostatic fields for efficient white light-emitting diodes,” Nature 406(6798), 865–868 (2000).
[CrossRef] [PubMed]

Phys. Rev. B

F. Bernardini, V. Fiorentini, and D. Vanderbilt, “Spontaneous polarization and piezoelectric constants of III-V nitrides,” Phys. Rev. B 56(16), R10024–R10027 (1997).
[CrossRef]

J. Seo Im, H. Kollmer, J. Off, A. Sohmer, F. Scholz, and A. Hangleiter, “Reduction of oscillator strength due to piezoelectric fields in GaN/AlxGa1-xN quantum wells,” Phys. Rev. B 57(16), R9435–R9438 (1998).
[CrossRef]

Phys. Status Solidi

K.-C. Kim, M. C. Schmidt, H. Sato, F. Wu, N. Fellows, M. Saito, K. Fujito, J. S. Speck, S. Nakamura, and S. P. DenBaars, “Improved electroluminescence on nonpolar m -plane InGaN/GaN quantum wells LEDs,” Phys. Status Solidi 1, 125–127 (2007) (RRL).

Thin Solid Films

Y. Jung, M. Mastro, J. Hite, C. R. Eddy, and J. Kim, “Electrical and structural characterizations of non-polar AlGaN/GaN heterostructures,” Thin Solid Films 518(6), 1747–1750 (2010).
[CrossRef]

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Figures (5)

Fig. 1
Fig. 1

(A). Schematic diagram of heteroepitaxial a-plane InGaN/GaN LED structure (B). Schematic diagram of GaN planes showing c-axis, c-plane and a-plane. (C) Microscope image of the processed a-plane InGaN/GaN LED.

Fig. 2
Fig. 2

SEM images in the direction of + c-axis [0001] of the mesa sidewall of LED samples (A) before and (B) after 5 min etching.

Fig. 3
Fig. 3

SEM images of PEC textured LED samples in the directions of (A) + c-axis [0001], (B) + m-direction [1-100], and (C) –c-axis [000-1].

Fig. 4
Fig. 4

The optical output powers of control and PEC textured LED samples for 5 min, measured on-wafer at the current injection of 20mA.

Fig. 5
Fig. 5

The comparison of radiation patterns of control and PEC textured a-plane LEDs, measured in m-axis and c-axis rotations.

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