ZnSe-ZnS应变超晶格的光致发光

PHOTOLUMINESCENCE OF ZnSe-ZnS STRAINED-LAYER SUPERLATTICES

本文讨论了使用常压金属氧化物化学汽相沉积(MOCVD)技术生长的ZnSe-ZnS应变超晶格的发光特性。ZnSe-ZnS应变超晶格的发射光谱,在高密度激发下通常仅存在一个发射峰;在低密度激发下除带边发射之外,还存在深中心的发射;与低密度激发相比,高激发下发光峰值红移且其半高宽展宽,高质量的ZnSe-ZnS应变超晶格在低激发下,带边发光很强,而深中心发射能被大大抑制,我们观测到一个新的激子发射峰,考虑应变效应与量子限制效应,本文将这一新的发射峰归结为与n=1的轻空穴激子有关的复合发光。

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.