关于GaAs的低迁移率问题

测量了5个不掺杂LPE-GaAs样品的电子迁移率温度关系,发现不同样品的诸曲线有互相交叉的现象,只用离化杂质散射一种非本征机制难于解释它。因此,假设未知散射中心(mobilitykiller)的存在看来是必要的。由于被研究的样品的纯度已相当高,Stringfellow等人所假设的杂质中心元胞势散射可以忽略不计。分析了光照对77K温度下电子浓度和迁移率的影响,认为未知散射中心可能是样品微观不均匀性造成的空间电荷区。关键词：

ON THE LOW MOBILITY OF GaAs

The temperature dependence of electron mobility on 5 undoped LPE-GaAs samples has been measured. It was found that the experimental curves cross each other and this is difficult to explain by only one extrinsic scattering mechanism (ionized impurity scattering). Therefore, it's necessary to assume another extrinsic scattering mechanism, so called mobility killer. Because the samples we used are rather pure, the central-cell scattering suggested by Stringfellow et al. can certainly be neglected. The effect of illumination on the electron concentration and mobility at 77 K has been studied and it is considered that the nature of mobility killer is probably the spacecharge regior caused by the microscopic inhomogeneities in samples.