瞬态C-V方法对Al_xGa_(1-x)As中DX中心的研究

本文指出DX中心电容测量中边区的重要性,提出一种新的瞬态C-V方法,可以用来测量DX中心浓度、导带电子浓度和边区的空间电荷分布及导带电子浓度随温度的变化关系,并由此导出测量DX中心热电离能的方法。另外,还对DX中心正∪和负∪两种模型的理论分析和实验结果进行了比较,得出不同模型所应满足的附加条件。

A New Transient V-C Method for Study of DX Centers in Al_xGa_(1-x)As

We present in this paper the importance of the edge region in capacitance measurement ofDX centers and the improvement of the step-wise charge distribution of the edge region. A newtransient C-V method is used to measure the density of DX cemters, density of bulk electrons inconduction band and the space charge distribution n the depletion region at a constant reversebais The temperature dependence of the density of bulk electrons in conduction band has alsobeen obtained. The thermal ionization energy of DX centers can be derived from these results.On the other hand, the comparison of the experimen(?)s and the theoretical curves derived fromthe negative U and positive U models of DX centers have been made and the conclusions areconsistent with our previous analysis of Hall experiments.In order to fit the theoretical curvesto the experimental data, compensating acceptors in the case of+U model, or other kind ofshallow donors in the case of-U model should be considered.