II-VI多量子阱中局域化激子的受激发射

Study on Emissions from Localized Excitons in ⅠⅠ ⅤⅠ Multiple Quantum Wells

通过对ＺｎｘＣｄ１－ｘＴｅ－ＺｎＴｅ多量子阱样品的光泵受激发射研究讨论了材料中激子局域态对受激发射激子过程以及受激发射特性的影响。两块不同组份和不同局域态密度的ＺｎＣｄＴｅ－ＺｎＴｅ多量子阱样品受激发射过程都是ｎ＝１重空穴激子参与的一系列过程，但在Ｚｎ０．６７Ｃｄ０．３３Ｔｅ－ＺｎＴｅ中发现了激子－激子散射的受激发射过程，而在Ｚｎ０．７８Ｃｄ０．２２Ｔｅ－ＺｎＴｅ中没有发现这一受激发射的激子过程。ｘ＝０．６７的样品中具有较高的局域化激子密度，其受激发射具有较高的阈值。

In this paper, the effects of density of localized exciton states on stimulated emission processes have been reported. In our experiments, two samples of  Zn x Cd 1-x Te ZnTe  mutiple quantum wells which with different concentration are employed, and the stimulated emissions from the localizid states are observed in each of them. The density of localized exciton states in Zn 0.67 Cd 0.33 Te ZnTe MQWs is much greater than that in Zn 0.78 Cd 0.22 Te ZnTe MQWs. The stimulated emission processes was found to be an exciton exciton scattering processes, but it was not found in Zn 0.78 Cd 0.22 Te ZnTe MQWs. It seems to be very important for localized exciton to create stimulated emissions, but too high density of localized exciton states will greatly increase the threshold. In a word, the density of localized exciton states may greatly affect the stimulated emissions.