摘要
平均键能模型是一种建立在数值基础上的用来确定半导体异质界面能带偏移的模型方法。本文首先对这一模型方法的物理基础进行了理论分析,并给予其完整的物理解释。通过与TB“pinned”模型、介电隙能级(DME)模型以及电中性点(CNP)模型的比较,揭示了各模型之间的相互关系,并分析了平均键能模型的优点及其局限性。在此基础上,本文应用这一模型方法对二十七种异质界面的价带偏移值进行了全面的计算,并对结果进行了广泛的分析和比较。结果表明:(1)阳离子浅d轨道是影响价带偏移理论值的一个重要因素;(2)界面偶极子势是决定异质界面价带偏移值的一个关键要素;(3)在与实验的比较上,平均键能模型的准确性优于几种其它的模型方法;(4)平均键能模型不适用于不具有sp^3杂化特性的材料系统。
In this paper, we present a full explanation for the average-bond-energy (ABE) model, which was developed, on the basis of numerical calculations, for the determination of valence-band offsets at heterointerfaces. By comparing it with the TB' pinned' model, the dielectric-midgap-energy model, and the charge-neutrality-point model, the relations between the four model theories are shown, and the advantages and limitationsof the ABE model are discussed. In this paper, the ABE model is applied to determining the valence-band offsets at 27 lattice-matched heterointerfaces systematically. The results show: (1)the cation shallow d orbitals play an important role in determining the theoretical values of valence-band offsets; (2)the interface dipole potential is an important contribution to the valence-band offset; (3)the results of ABE model are in good agreement with relevant experimental data, and the accuracy seems to be better than that of several other model theories; (4)the ABE model is not suitable to material systems which do not possess the character of sp3 hybridization.
出处
《发光学报》
EI
CAS
CSCD
北大核心
1996年第4期299-310,共12页
Chinese Journal of Luminescence
关键词
能带不连续性
半导体
异质界面
平均键能
band offsets, semiconductor heterointerfaces, ab initio calculations
