Optical Properties of Molecular Beam Epitaxy Grown ZnSe on GaAs

Abstract

Photoluminescence studies of molecular beam epitaxy grown ZnSe-on-GaAs layers are presented. Tle high sensitivity of the PL technique allowed for identification unintentional dopants in pure ZnSe sample. Characteristic photoluminescence lines due to extended defects were observed. The experimental results obtained show a correlation between intentional doping level and extended defects concentration. We conclude also that even though molecular beam epitaxy layers are grown at low temperature, the self-ckpensation mechanism may still be important. For heavily doped sample edge emission is deactivated likely due to efficient energy transfer link with deep donor-acceptor pair bands.

Oscillatory Regularity of Charge Carrier Trap Energy Spectra in ZnSe Single Crystals

“…A significant change in the XRL spectra is observed at room temperature due to temperature quenching of the luminescence. The typical EEE is observed in all studied ZnSe samples at low temperatures [14,18,19]; this emission is detected as a band with a maximum at 465 nm at liquid nitrogen temperature. EEE is conditioned by the excitons that are free or localized on the shallow donors [20,21].…”

“…In the ZnSe crystals in which the recombination emission bands with maxima at 635 nm and 820 nm are weak, the intensive emission of DAPs is usually observed [18,23,24] in the wavelength range of 470 nm to 550 nm. The energy levels of the donors in ZnSe are conditioned by the Zn i defects, and the acceptor centres may be conditioned by O Se or (O Se -D).…”