Comparison Between Homo-And Hetero-Epitaxial Layers by Photoreflectance Spectroscopy


MOCVD grown GaAs and InP epitaxial layers have been studied using photoreflectance spectroscopy. Homogeneous and heterogeneous structures were employed to investigate the influence of the mismatch induced strain and dislocations. All the tested spectra contained a sharp peak related to the fundamental absorption edge and a pronounced Franz-Keldysh oscillation. The data analysis revealed a consistent difference in bandgap, temperature coefficients of the bandgap, and surface electric field, in the order of the degree of mismatch. For GaAs/GaAs and GaAs/Si samples, the bandgaps derived from the three point method were 1.436 and 1.324eV, respectively. Values of 1.334, 1.325, and 1.294 eV for the bandgap were found for InP/InP, InP/GaAs, and InP/GaAs/Si, respectively. For GaAs epitaxial layers, the intensity of the surface field bore a ratio of 1.18:1 between GaAs and Si substrates. For InP epitaxial layers, the ratio was 1.23:1.12:1 in the sequence of InP, GaAs, and GaAs/Si substrates. Such a measure must be related to the mismatch in the heteroepitaxy structures. A shoulderlike peak, 18-23 meV below the gap-energy peak (Eo), was found for GaAs samples, which could be impurity related. A broad shoulder-like peak 30 meV below the fundamental absorption edge was also observed only for InP/GaAs/Si and hence attributed to some shallow defect levels induced by antiphase disorder.

This is a preview of subscription content, access via your institution.


  1. 1.

    J.C.C. Fan and J.M. Poate eds., "Heteroepitaxy on Silicon", MRS Symposia Proceeding, 67, Pittsburgh (1986).

  2. 2.

    J.C.C. Fan, J.M. Philips and B.Y. Tsaur eds., "Heteroepitaxy on Silicon II", MRS Symposia Proceeding, 91, Pittsburgh (1987).

  3. 3.

    A. Yamamoto, M. Uchida, and M. Yamaguchi, Optoelectron. Dev. and Tech., 1, 41 (1986).

    CAS  Google Scholar 

  4. 4.

    M.K. Lee, K.C. Huang, D.S. Wuu, H.H. Tung and K.Y. Yu, Appl. Phys. Lett., 52, 880 (1988).

    CAS  Article  Google Scholar 

  5. 5.

    C.J. Keavney, S.M. Vernon, V.E. Haven, S.J. Wojtczuk and M.M. Al-Jassim, Appl. Phys. Lett., 54, 1139 (1989).

    CAS  Article  Google Scholar 

  6. 6.

    M. Sugo, M. Yamaguchi and M.M. Al-Jassim, J. Crystal Growth, 99, 365 (1990).

    CAS  Article  Google Scholar 

  7. 7.

    N. Bottka, D.K. Gaskill, R.S. Sillmon, R. Henry and R. Glosser, J. Electron. Mater., 17, 161 (1988).

    CAS  Article  Google Scholar 

  8. 8.

    F.H. Pollak and H. Shen, J. Electron. Mater., 19, 399 (1990).

    CAS  Article  Google Scholar 

  9. 9.

    N. Bottka, D.K. Gaskill, R.J.M. Griffiths, R.R. Bradley. T.B. Joyce, C. Ito and D. McIntyre, J. Crystal Growth, 93, 481 (1988).

    CAS  Article  Google Scholar 

  10. 10.

    A. Dimoulas, P. Tzanetakis, K. Georgakilas, O.J. Glembocki and A. Christou, J. Appl. Phys., 67, 4389 (1990).

    CAS  Article  Google Scholar 

  11. 11.

    P. Panayotatos, A. Georgakilas, J-L Mourrain and A. Christou, Presented at the Int. Conf. on Physical Concepts of Material for Novel Optoelectronic Device Applications, SPIE- The International Society for Optical Engineering, Eurogress Aachen, FRG, Oct. 28 - Nov. 2, (1990).

  12. 12.

    J.L. Shay, Phys. Rev. B2, 803 (1970).

    Article  Google Scholar 

  13. 13.

    D.E. Aspnes and J.E. Rowe, Phys. Rev. Lett., 27, 188 (1971).

    CAS  Article  Google Scholar 

  14. 14.

    H. Okamato, T. Oh’hama, Y. Kadota and Y. Ohmachi, Jpn. J. Appl. Phys., 29, 1052 (1990).

    Article  Google Scholar 

Download references


The authors wish to acknowledge S.M. Vernon at Spire Corp. for providing the samples.

Author information



Corresponding author

Correspondence to K. L. Jiao.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Jiao, K.L., Shi, Z.Q. & Anderson, W. Comparison Between Homo-And Hetero-Epitaxial Layers by Photoreflectance Spectroscopy. MRS Online Proceedings Library 209, 713–717 (1990).

Download citation