Abstract In this work the effects of filling the surface energy states in AlGaAs/GaAs heterostructures on the depletion layer are reported. The depletion layer width was varied from 49 to 10 nm as determined by Raman spectroscopy, allowing to discern their effect on the generation of Franz-Keldysh oscillations observed by photoreflectance spectroscopy. It is found that the photoreflectance modulation process of built-in electric fields at surface is negligible when the surface-levels are filled. This work demonstrates the relationship between the surface-states density, the surface states capability of capture carriers and the layer sequence of the heterostructure. These parameters need to be considered in order to get an adequate analysis of the photoreflectance spectrum of heterostructures. It is shown that if a nearly full-filled condition in the available surface energy levels is established, the Franz-Keldysh oscillations produced by the modulation of the built-in electric field intensity disappears as a result of the reduction in the photogenerated carrier density in the photoreflectance measurement.

中文翻译：

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MBE生长的AlGaAs/GaAs异质结构中近表面耗尽层的光谱分析

摘要 在这项工作中，报告了填充 AlGaAs/GaAs 异质结构中的表面能态对耗尽层的影响。耗尽层宽度从 49 到 10 nm 不等，由拉曼光谱确定，允许辨别它们对​​光反射光谱观察到的 Franz-Keldysh 振荡产生的影响。发现当表面能级被填充时，表面内建电场的光反射调制过程可以忽略不计。这项工作证明了表面态密度、捕获载流子的表面态能力和异质结构的层序之间的关系。需要考虑这些参数，以便对异质结构的光反射光谱进行充分分析。