PHOTOLUMINESCENCE OF ZnSe-ZnS STRAINED-LAYER SUPERLATTICES

Abstract

The photoluminescence (PL) emission spectra of ZnSe-ZnS strained-layer surerlattices (SLS) grown by atmospheric pressure metal organic chemical vapor deposition (AP-MOCVD) have been studied in this paper. With the high density excitation (N2-Laser 337.1nm), the PL of the SLS consist in only one emission peak due to the n = 1 heavy hole excitons recombination, and with the low density excitation (high pressure Hg-Lamp 365.nm) the PL consist of both the band-edge emission and the deep-centre emission. One gap-edge emission peak without the deep-centre emission have been observed in the low-excitation PL, and the sample was thought to have good crystaline quality. The subbands of ZnSe-ZnS SLS were calculated using the theoies of the stress-induced baud structures and the Kronig-Penney band model. The two emission peaks, the energy of which are greater than the energy-gap of ZnSe single crystal films in the absence of strain, were observed in the PL spectra of ZnSe-ZnS SLS for the first time. According to the subband calculation, the two peaks were thought to be caused by the transitions between the n= 1 electronic subband and the n= 1 heavy, light holes' subbands, respectively.