Abstract

We analyze the IR absorption of tensile-strained, n-type Ge for Si-compatible laser applications. A strong intervalley scattering from the indirect L valleys to the direct Γ valley in n+ Ge-on-Si is reported for the first time to our knowledge. The intervalley absorption edge is in good agreement with the theoretical value. On the other hand, we found that the classical λ2-dependent Drude model of intravalley free-carrier absorption (FCA) breaks down at λ<15μm. A first-principle model has to be employed to reach a good agreement with the experimental data. The intravalley FCA loss is determined to be <20cm1 for n=4×1019cm3 at λ=1.51.7μm, an order lower than the results from Drude model. The strong LΓ intervalley scattering favors electronic occupation of the direct Γ valley, thereby enhancing optical gain from the direct gap transition of Ge, while the low intravalley free-electron absorption at lasing wavelengths leads to low optical losses. These two factors explain why the first electrically pumped Ge-on-Si laser achieved a higher net gain than the theoretical prediction using λ2-dependent free-carrier losses of bulk Ge and indicate the great potential for further improvement of Ge-on-Si lasers.

© 2013 Optical Society of America

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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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    [CrossRef]
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2012

2010

2009

2008

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

2007

1998

C.-Y. Tsai, C.-H. Chen, T. L. Sung, T.-Y. Wu, and F.-P. Shih, IEEE. J. Quantum Electron. 34, 552 (1998).
[CrossRef]

1993

B. Garrido, J. A. Moreno, J. Samitier, and J. R. Morante, Appl. Surf. Sci. 63, 236 (1993).
[CrossRef]

1992

A. Haug, Semicond. Sci. Technol. 7, 373 (1992).
[CrossRef]

1991

1970

A. R. Bean, R. C. Newman, and R. S. Smith, J. Phys. Chem. Solids 31, 739 (1970).
[CrossRef]

J. D. Wiley and M. Didqmenico, Phys. Rev. B 1, 1655 (1970).
[CrossRef]

1962

C. Haas, Phys. Rev. 125, 1965 (1962).
[CrossRef]

1961

W. G. Spitzer, F. A. Trumbore, and R. A. Logan, J. Appl. Phys. 32, 1822 (1961).
[CrossRef]

1959

W. G. Spitzer and J. M. Whelan, Phys. Rev. 114, 59 (1959).
[CrossRef]

1958

R. Rosenberg and M. Lax, Phys. Rev. 112, 843 (1958).
[CrossRef]

1957

W. Spitzer and H. Y. Fan, Phys. Rev. 108, 268 (1957).
[CrossRef]

1956

H. Y. Fan, W. Spitzer, and R. J. Collin, Phys. Rev. 101, 566 (1956).
[CrossRef]

W. Kaiser, P. H. Keck, and C. F. Lange, Phys. Rev. 101, 1264 (1956).
[CrossRef]

Ahn, D. H.

Aleksandrov, B.

Beals, M.

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

D. H. Ahn, C. Y. Hong, J. F. Liu, M. Beals, W. Giziewicz, L. C. Kimerling, and J. Michel, Opt. Express 15, 3916 (2007).
[CrossRef]

Bean, A. R.

A. R. Bean, R. C. Newman, and R. S. Smith, J. Phys. Chem. Solids 31, 739 (1970).
[CrossRef]

Bernardis, S.

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

Bessette, J. T.

Cai, Y.

R. E. Camacho-Aguilera, Y. Cai, N. Patel, J. T. Bessette, M. Romagnoli, L. Kimerling, and J. Michel, Opt. Express 20, 11316 (2012).
[CrossRef]

Y. Cai, Z. Han, X. Wang, R. Camacho-Aguilera, L. C. Kimerling, J. Michel, and J. Liu, “Analysis of threshold current behavior of bulk and quantum well germanium laser structures,” IEEE J. Sel. Top. Quantum Electron., doc. ID JSTQE-INV-SL-04810-2012.R1 (to be published).

Camacho-Aguilera, R.

J. F. Liu, X. Sun, R. Camacho-Aguilera, L. C. Kimerling, and J. Michel, Opt. Lett. 35, 679 (2010).
[CrossRef]

Y. Cai, Z. Han, X. Wang, R. Camacho-Aguilera, L. C. Kimerling, J. Michel, and J. Liu, “Analysis of threshold current behavior of bulk and quantum well germanium laser structures,” IEEE J. Sel. Top. Quantum Electron., doc. ID JSTQE-INV-SL-04810-2012.R1 (to be published).

Camacho-Aguilera, R. E.

Chen, C.-H.

C.-Y. Tsai, C.-H. Chen, T. L. Sung, T.-Y. Wu, and F.-P. Shih, IEEE. J. Quantum Electron. 34, 552 (1998).
[CrossRef]

Cheng, J.

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

Collin, R. J.

H. Y. Fan, W. Spitzer, and R. J. Collin, Phys. Rev. 101, 566 (1956).
[CrossRef]

Didqmenico, M.

J. D. Wiley and M. Didqmenico, Phys. Rev. B 1, 1655 (1970).
[CrossRef]

Fan, H. Y.

W. Spitzer and H. Y. Fan, Phys. Rev. 108, 268 (1957).
[CrossRef]

H. Y. Fan, W. Spitzer, and R. J. Collin, Phys. Rev. 101, 566 (1956).
[CrossRef]

Garrido, B.

B. Garrido, J. A. Moreno, J. Samitier, and J. R. Morante, Appl. Surf. Sci. 63, 236 (1993).
[CrossRef]

Giziewicz, W.

Gunde, M. K.

Haas, C.

C. Haas, Phys. Rev. 125, 1965 (1962).
[CrossRef]

Han, Z.

Y. Cai, Z. Han, X. Wang, R. Camacho-Aguilera, L. C. Kimerling, J. Michel, and J. Liu, “Analysis of threshold current behavior of bulk and quantum well germanium laser structures,” IEEE J. Sel. Top. Quantum Electron., doc. ID JSTQE-INV-SL-04810-2012.R1 (to be published).

Haug, A.

A. Haug, Semicond. Sci. Technol. 7, 373 (1992).
[CrossRef]

Hong, C. Y.

Kaiser, W.

W. Kaiser, P. H. Keck, and C. F. Lange, Phys. Rev. 101, 1264 (1956).
[CrossRef]

Keck, P. H.

W. Kaiser, P. H. Keck, and C. F. Lange, Phys. Rev. 101, 1264 (1956).
[CrossRef]

Kimerling, L.

Kimerling, L. C.

J. F. Liu, L. C. Kimerling, and J. Michel, Semicond. Sci. Technol. 27, 094006 (2012).
[CrossRef]

J. F. Liu, X. Sun, R. Camacho-Aguilera, L. C. Kimerling, and J. Michel, Opt. Lett. 35, 679 (2010).
[CrossRef]

J. F. Liu, X. Sun, L. C. Kimerling, and J. Michel, Opt. Lett. 34, 1738 (2009).
[CrossRef]

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

D. H. Ahn, C. Y. Hong, J. F. Liu, M. Beals, W. Giziewicz, L. C. Kimerling, and J. Michel, Opt. Express 15, 3916 (2007).
[CrossRef]

J. Liu, X. Sun, D. Pan, X. X. Wang, L. C. Kimerling, T. L. Koch, and J. Michel, Opt. Express 15, 11272 (2007).
[CrossRef]

Y. Cai, Z. Han, X. Wang, R. Camacho-Aguilera, L. C. Kimerling, J. Michel, and J. Liu, “Analysis of threshold current behavior of bulk and quantum well germanium laser structures,” IEEE J. Sel. Top. Quantum Electron., doc. ID JSTQE-INV-SL-04810-2012.R1 (to be published).

Koch, T. L.

Lange, C. F.

W. Kaiser, P. H. Keck, and C. F. Lange, Phys. Rev. 101, 1264 (1956).
[CrossRef]

Lax, M.

R. Rosenberg and M. Lax, Phys. Rev. 112, 843 (1958).
[CrossRef]

Liu, J.

J. Liu, X. Sun, D. Pan, X. X. Wang, L. C. Kimerling, T. L. Koch, and J. Michel, Opt. Express 15, 11272 (2007).
[CrossRef]

Y. Cai, Z. Han, X. Wang, R. Camacho-Aguilera, L. C. Kimerling, J. Michel, and J. Liu, “Analysis of threshold current behavior of bulk and quantum well germanium laser structures,” IEEE J. Sel. Top. Quantum Electron., doc. ID JSTQE-INV-SL-04810-2012.R1 (to be published).

Liu, J. F.

Logan, R. A.

W. G. Spitzer, F. A. Trumbore, and R. A. Logan, J. Appl. Phys. 32, 1822 (1961).
[CrossRef]

Michel, J.

J. F. Liu, L. C. Kimerling, and J. Michel, Semicond. Sci. Technol. 27, 094006 (2012).
[CrossRef]

R. E. Camacho-Aguilera, Y. Cai, N. Patel, J. T. Bessette, M. Romagnoli, L. Kimerling, and J. Michel, Opt. Express 20, 11316 (2012).
[CrossRef]

J. F. Liu, X. Sun, R. Camacho-Aguilera, L. C. Kimerling, and J. Michel, Opt. Lett. 35, 679 (2010).
[CrossRef]

J. F. Liu, X. Sun, L. C. Kimerling, and J. Michel, Opt. Lett. 34, 1738 (2009).
[CrossRef]

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

D. H. Ahn, C. Y. Hong, J. F. Liu, M. Beals, W. Giziewicz, L. C. Kimerling, and J. Michel, Opt. Express 15, 3916 (2007).
[CrossRef]

J. Liu, X. Sun, D. Pan, X. X. Wang, L. C. Kimerling, T. L. Koch, and J. Michel, Opt. Express 15, 11272 (2007).
[CrossRef]

Y. Cai, Z. Han, X. Wang, R. Camacho-Aguilera, L. C. Kimerling, J. Michel, and J. Liu, “Analysis of threshold current behavior of bulk and quantum well germanium laser structures,” IEEE J. Sel. Top. Quantum Electron., doc. ID JSTQE-INV-SL-04810-2012.R1 (to be published).

Morante, J. R.

B. Garrido, J. A. Moreno, J. Samitier, and J. R. Morante, Appl. Surf. Sci. 63, 236 (1993).
[CrossRef]

Moreno, J. A.

B. Garrido, J. A. Moreno, J. Samitier, and J. R. Morante, Appl. Surf. Sci. 63, 236 (1993).
[CrossRef]

Newman, R. C.

A. R. Bean, R. C. Newman, and R. S. Smith, J. Phys. Chem. Solids 31, 739 (1970).
[CrossRef]

Pan, D.

Patel, N.

Pomerene, A.

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

Romagnoli, M.

Rosenberg, R.

R. Rosenberg and M. Lax, Phys. Rev. 112, 843 (1958).
[CrossRef]

Samitier, J.

B. Garrido, J. A. Moreno, J. Samitier, and J. R. Morante, Appl. Surf. Sci. 63, 236 (1993).
[CrossRef]

Shih, F.-P.

C.-Y. Tsai, C.-H. Chen, T. L. Sung, T.-Y. Wu, and F.-P. Shih, IEEE. J. Quantum Electron. 34, 552 (1998).
[CrossRef]

Smith, R. S.

A. R. Bean, R. C. Newman, and R. S. Smith, J. Phys. Chem. Solids 31, 739 (1970).
[CrossRef]

Spitzer, W.

W. Spitzer and H. Y. Fan, Phys. Rev. 108, 268 (1957).
[CrossRef]

H. Y. Fan, W. Spitzer, and R. J. Collin, Phys. Rev. 101, 566 (1956).
[CrossRef]

Spitzer, W. G.

W. G. Spitzer, F. A. Trumbore, and R. A. Logan, J. Appl. Phys. 32, 1822 (1961).
[CrossRef]

W. G. Spitzer and J. M. Whelan, Phys. Rev. 114, 59 (1959).
[CrossRef]

Sun, R.

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

Sun, X.

Sung, T. L.

C.-Y. Tsai, C.-H. Chen, T. L. Sung, T.-Y. Wu, and F.-P. Shih, IEEE. J. Quantum Electron. 34, 552 (1998).
[CrossRef]

Trumbore, F. A.

W. G. Spitzer, F. A. Trumbore, and R. A. Logan, J. Appl. Phys. 32, 1822 (1961).
[CrossRef]

Tsai, C.-Y.

C.-Y. Tsai, C.-H. Chen, T. L. Sung, T.-Y. Wu, and F.-P. Shih, IEEE. J. Quantum Electron. 34, 552 (1998).
[CrossRef]

Wang, X.

Y. Cai, Z. Han, X. Wang, R. Camacho-Aguilera, L. C. Kimerling, J. Michel, and J. Liu, “Analysis of threshold current behavior of bulk and quantum well germanium laser structures,” IEEE J. Sel. Top. Quantum Electron., doc. ID JSTQE-INV-SL-04810-2012.R1 (to be published).

Wang, X. X.

Whelan, J. M.

W. G. Spitzer and J. M. Whelan, Phys. Rev. 114, 59 (1959).
[CrossRef]

Wiley, J. D.

J. D. Wiley and M. Didqmenico, Phys. Rev. B 1, 1655 (1970).
[CrossRef]

Wu, T.-Y.

C.-Y. Tsai, C.-H. Chen, T. L. Sung, T.-Y. Wu, and F.-P. Shih, IEEE. J. Quantum Electron. 34, 552 (1998).
[CrossRef]

Appl. Opt.

Appl. Surf. Sci.

B. Garrido, J. A. Moreno, J. Samitier, and J. R. Morante, Appl. Surf. Sci. 63, 236 (1993).
[CrossRef]

IEEE. J. Quantum Electron.

C.-Y. Tsai, C.-H. Chen, T. L. Sung, T.-Y. Wu, and F.-P. Shih, IEEE. J. Quantum Electron. 34, 552 (1998).
[CrossRef]

J. Appl. Phys.

W. G. Spitzer, F. A. Trumbore, and R. A. Logan, J. Appl. Phys. 32, 1822 (1961).
[CrossRef]

J. Phys. Chem. Solids

A. R. Bean, R. C. Newman, and R. S. Smith, J. Phys. Chem. Solids 31, 739 (1970).
[CrossRef]

Nat. Photonics

J. F. Liu, M. Beals, A. Pomerene, S. Bernardis, R. Sun, J. Cheng, L. C. Kimerling, and J. Michel, Nat. Photonics 2, 433 (2008).
[CrossRef]

Opt. Express

Opt. Lett.

Phys. Rev.

W. Kaiser, P. H. Keck, and C. F. Lange, Phys. Rev. 101, 1264 (1956).
[CrossRef]

H. Y. Fan, W. Spitzer, and R. J. Collin, Phys. Rev. 101, 566 (1956).
[CrossRef]

R. Rosenberg and M. Lax, Phys. Rev. 112, 843 (1958).
[CrossRef]

C. Haas, Phys. Rev. 125, 1965 (1962).
[CrossRef]

W. Spitzer and H. Y. Fan, Phys. Rev. 108, 268 (1957).
[CrossRef]

W. G. Spitzer and J. M. Whelan, Phys. Rev. 114, 59 (1959).
[CrossRef]

Phys. Rev. B

J. D. Wiley and M. Didqmenico, Phys. Rev. B 1, 1655 (1970).
[CrossRef]

Semicond. Sci. Technol.

A. Haug, Semicond. Sci. Technol. 7, 373 (1992).
[CrossRef]

J. F. Liu, L. C. Kimerling, and J. Michel, Semicond. Sci. Technol. 27, 094006 (2012).
[CrossRef]

Other

O. Madelung, ed., Physics of Group IV Elements and III–V Compounds, Vol. 17a of Landolt–Börnstein: Numerical Data and Functional Relationships in Science and Technology (Springer, 1982).

Y. Cai, Z. Han, X. Wang, R. Camacho-Aguilera, L. C. Kimerling, J. Michel, and J. Liu, “Analysis of threshold current behavior of bulk and quantum well germanium laser structures,” IEEE J. Sel. Top. Quantum Electron., doc. ID JSTQE-INV-SL-04810-2012.R1 (to be published).

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Figures (3)

Fig. 1.
Fig. 1.

(a), (b) Transmittance spectra of 0.25% tensile-strained n+ Ge-on-Si samples D1–D3 together with their SSP Si substrates as references.

Fig. 2.
Fig. 2.

IR absorption spectrum of Ge thin film with n=1×1019cm3 derived from the transmittance data of D1. Regimes I–IV are dominated by intra-L-valley FCA, LΓ IVSA, indirect gap+intervalley scattering absorption, and direct gap absorption, respectively.

Fig. 3.
Fig. 3.

Theoretical and experimental intervalley energy difference between L and Γ valleys as a function of doping concentration. The inset schematically illustrates the phenomenon of LΓ IVSA in n+ Ge.

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