量子化极限情况下MOS反型层二维电子气定域态电子电导率σxx的低频效应

本文分析了量子化极限情况下MOS反型层二维电子气(2DEG)定域态电子电导率的频率特性。主要内容:(1)用费密分布函数随频率变化导出了在2DEG两种主要导电过程的频率特性。即向迁移率边激发导电过程电导率σ_ME(ω)和可变程跳跃导电过程电导率σ_VRH(ω)。发现:σ_ME(ω)和σ_VRH(ω)是一个复数。(2)说明了σ_ME(ω)有较长时间常数τ_n,对应一个低频过程。σ_VRH(ω)有较短时间常数,对应一个高频过程。(3)理论与实验作了比较,拟合结果表明,在实验条件下,向迁移率边E_c激发时间常数τ_n 3.6×10^-6。 关键词：

THE LOW FREQUENCY EFFECTS OF TRANSVERSE CONDUCTIVITY OF ELECTRON IN LOCALIZED STATE OF THE TWO DIMENSIONAL ELECTRON GAS IN MOS INVERSION LAYER UNDER THE CONDITION OF QUANTIZED LIMIT

In this article, we analyze the frequency characteristics of electron conductivity in localized states of the 2 dimensional electron gas (2DEG) in MOS inversion layer under the condition of quantized limit. Based on the frequency dependence of Fermi distribution function, we derived the frequency characteristics of the two dominant conduction processes, i.e., the conductivity due to the process of thermally exciting to the mobility edge, σ_ME (ω),and that due to variable range hopping process, σ_VRH(ω). We found that σ_ME(ω) and σ_VRH (ω) are both complex functions. The time constant of σ_ME(ω), τ_n, is longer, corresponding to a low frequency process. And that of σ_VRH(ω) is much shorter, corresponding to high frequency process. The theoretical curve is compared with experimental data. It is found that in order to fit the theoretical curve to the experimental one, the time constant τ_n should be approximately 3.6 ×10^-6 s.