Hostname: page-component-848d4c4894-sjtt6 Total loading time: 0 Render date: 2024-06-18T09:55:13.813Z Has data issue: false hasContentIssue false

Excitation Wavelength Dependent Raman Scattering in Low and Highly Degenerate InN Films

Published online by Cambridge University Press:  01 February 2011

V.M. Naik
Affiliation:
Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, Ml 48128
H. Dai
Affiliation:
Department of Physics and Astronomy, Wayne Stale University, Detroit, Ml 48201
R. Naik
Affiliation:
Department of Physics and Astronomy, Wayne Stale University, Detroit, Ml 48201
D.B. Haddad
Affiliation:
Department of Electrical and Computer Engineering, Wayne Slate University, Detroit, Ml 48202
J.S. Thakur
Affiliation:
Department of Electrical and Computer Engineering, Wayne Slate University, Detroit, Ml 48202
G.W. Auner
Affiliation:
Department of Electrical and Computer Engineering, Wayne Slate University, Detroit, Ml 48202
H. Lu
Affiliation:
Department of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14583
W.J. Schaff
Affiliation:
Department of Electrical and Computer Engineering, Cornell University, Ithaca, NY 14583
Get access

Abstract

The Raman spectra of low and highly degenerate InN films grown by conventional Molecular Beam Epitaxy (MBE) and Plasma Source Molecular Beam Epitaxy (PSMBE) have been studied using visible (514.5 nm) and near infrared (785 nm) excitation wavelengths. The MBE grown InN films have a low electron carrier concentration, ne < 2.0 × 1019 cm−3, exhibiting an optical bandgap absorption edge of 0.6 to 0.7 eV. On the other hand PSMBE grown InN samples are highly degenerate with ne > 3 × 1020 cm−3 with an observed optical bandgap ranging from 1.5 to 1.9 eV. Raman spectra of low degenerate InN films show sharp E2 and A1(LO) modes whereas spectra of highly degenerate InN films show rather broad features indicating the presence of a large number of structural defects. In the latter samples a resonance enhanced Raman scattering is observed especially with 785 nm excitation energy, where the excitation energy matches the optical energy bandgap. Another interesting observation is that the expected coupled plasmon LO-phonon modes are not detected in these films, rather a phonon mode is observed at the location of the unscreened A1(LO) mode. The observation of unscreened LO-phonon, and the absence of coupled plasmon LO-phonon modes have been attributed to Landau damping of the higher energy mode and coupling of the lower energy mode with the electron-hole pair excitations leading to the emergence of a mode very close to the A1(LO) mode.

Type
Research Article
Copyright
Copyright © Materials Research Society 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

REFERENCES

1. Strite, S. and Morkoc, H., J. Vac. Sci. Technol. B 10, 1237, 1992.Google Scholar
2. Qian, S.Z., Shen, W.Z., Ogawa, H. and Guo, D.X., J. Phys. Condens. Matter, 16, R381, 2004.Google Scholar
3. Mamutin, V.V., Vekshin, V.A., Davydov, V. Yu, Ratnikov, V.V., Shubina, T.V., Ivanov, S. V., Kopev, P. S., Karlsteen, M., Soderwall, U., Willander, M., Phys. Stat. Sol. (a) 176, 247 (1999).Google Scholar
4. Lu, H., Schaff, W.J., Hwang, J., Wu, H., Yeo, W., Pharkya, A., and Eastman, L.F., Appl. Phys. Lett. 77, 2548 (2000)Google Scholar
5. Y. saito, Teraguchi, N., Suzuki, A., Araki, T. and Nanishi, Y., Jpn. J. Appl. Phys. Part 2, 40, L91 (2001)Google Scholar
6. Wu, J., Walukiewicz, W., Yu, K.M., Ager, J.W. III, Haller, E.E., Lu, H., Schaff, W.J., Saito, Y., and Nanishi, Y., Appl. Phys. Lett. 80, 3967 (2002).Google Scholar
7. Matsuoka, T., Okamoto, H., Nakano, M., Harima, H., Kurimoto, E., Appl. Phys. Lett. 81, 1246 (2002).Google Scholar
8. Yu Davydov, V., Klochikhin, A.A., Seisyan, R.P., Emetsev, V.V., et al., Phys. Stat. Sol. (b) 229, R1 (2002);Google Scholar
Davydov, V.Yu, Klochikhin, A.A., Emetsev, V.V., Ivanov, S.V., et al., Phys. Stat. Sol. (b) 230, R4 (2002).Google Scholar
9. Wu, J., Walukiewicz, W., Shan, W., Yu, K.M., Ager, J.W. III, Haller, E.E., Lu, H., and Schaff, W.J., Phys. Rev. B. 66, 201403 (2002).Google Scholar
10. Tansley, T. L. and Foley, C. P., J. Appl. Phys. 59, 3241 (1986).Google Scholar
11. Guo, Q. and Yoshida, A., Jpn. J. Appl. Phys. 33, 2453 (1994).Google Scholar
12. Haddad, D.B., Dai, H., Naik, R., Morgan, C., Naik, V.M., Thakur, J.S., Auner, G.W., Wenger, L.E., Lu, H., and Schaff, W.J., Mat. Res. Soc. Symp. Proc. Vol. 798, Y12.7.16 (2004);Google Scholar
Haddad, D., Thakur, J.S., Naik, V.M., Auner, G.W., Naik, R., and Wenger, L.E., Mat. Res. Soc. Symp. Proc. Vol. 743, L11.22.16, 2003.Google Scholar
13. Shubina, T.V., Ivanov, S.V., Jmerik, V.N., Solnyshkov, D.D., Vekshin, V.A., and Kopev, P.S., Vasson, A., Leymarie, J., Kavokin, A., Amano, H., Shimono, K., Kasic, A. and Monemar, B., Phys. Rev. Lett. 92, 117407–1 (2004).Google Scholar
14. Kuball, M., Pomeroy, J.W., Wintrebert-Fouquet, M., Butcher, K.S. A., Lu, H. and Schaff, W.J., J. Cryst. Growth. 269, 59, 2004.Google Scholar
15. Lu, H., Schaff, W.J., Hwang, H., Wu, H., Koley, G., and Eastman, L.F., Appl. Phys. Lett. 79, 1489 (2001).Google Scholar
16. Kaczmarczyk, G., Kaschner, A., Reich, S., Hoffmann, A., Thomsen, C., As, D.J., Lima, A.P., Shikora, D., Lischka, K., Averbeck, R. and Riechert, H., Appl. Phys. Lett. 76, 2123(2000).Google Scholar
17. Imanuchi, T., Shiraishi, T. and Tu Davydov, V., Solid State Comm. 110, 491 (1999).Google Scholar
18. Thakur, J.S., Haddad, D., Naik, V.M., Naik, R. and Auner, G.W., J. of Appl. Phys. 95, 4795, 2004 Google Scholar
19. Thakur, J.S., Haddad, D.B., Naik, R., Auner, G.W., and Naik, V.M., submitted to Phys. Rev. B.Google Scholar