摘要
本文用光荧光光谱和激发光谱研究了分子束外延GaAs-GaAlAs多量子阱结构的界面特性。在极弱激发条件下,与界面相关的光谱特性可以分为三类:当样品界面较为平整时,光谱结构上出现明显的本征发光和杂质发光竞争现象;当样品界面起伏较大时,界面缺陷可成为激子束缚中心,阻止载流子向杂质能级扩散,光谱中只表现出较宽的本征发光峰;还有一种情况是界面缺陷使杂质在界面富集,光谱中出现较强的界面杂质发光。
The interface behavior in MBE Grown GaAs-GaAlAs MQW structures has been studied bymeans of photoluminescence and excitation spectrosoopy under extremely low excitation.Differentspectroscopic behavior has been found in different samples.For a sample with singlemonolayer fluctuation, a strong competition between intrinsic exciton luminescence and impurity-relatedemission is observed. However, for the samples with larger fluctuation, the interfacedisorder may become trapping center of excitons, preventing the exciton intralayermigration to impurities, resulting in a single broad intrinsic luminescence peak. On the otherhand the degradation of smoothness of the interface may accumulate impurities on interface,which gives a strong interface-related extrisic emission in the spectrum.
基金
国家科委超晶格课题大基金
中国科学院超晶格课题重点基金
