The Effect of Substrate Misorientation Angle on the Band Gap Energies of II-VI Compound Semiconductors Grown by Molecular Beam Epitaxy

D. M. Chen ； C. S. Yang ； F. B. Chuang ； Y. W. Tzeng ； C. C. Wei ； C. S. Ro ； K. Y. Lan ； W. C. Chou ； W. H. Lan ； W. Y. Uen

《Chinese Journal of Physics》 38卷1期 (2000/02) Pp. 74-80

並列摘要

The effect of substrate misorientation angle (SMA) on the band gap energies of II-VI compound semiconductor epilayers, Zn1¡xMgxSe, Zn1¡xMnxSe, ZnSe1¡xTex, Zn1¡xCdxSe and ZnSe1¡xSx, was studied by optical spectroscopy. The band gap energies were found to increase with substrate misorientation (tilted) angle for Zn1¡xMgxSe, ZnSe1¡xTex, Zn1¡xCdxSe and ZnSe1¡xSx epilayers. While for the Zn1¡xMnxSe epilayers, the band gap energies decrease with SMA. Both the decrease (for Zn1¡xMnxSe epilayers) and increase (for the other epilayers) in band gap energy are attributed to the increasing incorporation of smaller ions as the SMA is increased. The dependence of the energy gap on the SMA is almost linear for ZnSe1¡xTex and Zn1¡xMnxSe epilayers. For Zn1¡xMgxSe and Zn1¡xCdxSe epilayers, the energy gap increases abruptly at a small tilt angle, then becomes insensitive to the SMA at a tilt angle larger than 10 degrees. In the case of the ZnSe1¡xSx epilayer, the situation is reversed. At small angles the SMA has little influence on the band gap energy. At a SMA larger than 10 degrees, the band gap energy increases suddenly. The sudden increase with SMA at a large tilt angle results from the abrupt increase in kink density which is a function of the square of the tilt angle. The energy difference between the energy gap of an epilayer grown on [100] substrate and an epilayer grown on [100] substrate with 15 degrees tilt toward [010] is largest (18 meV) for Zn1¡xMgxSe epilayers. For Zn1¡xMnxSe, ZnSe1¡xSx and ZnSe1¡xTex epilayers, the energy differences are about 5 meV.