AlN／GaN异质结的价带偏移计算

The Valence-band Offsets of Heterojunction AlN/GaN

用平均键能方法，研究了ＡｌＮ与ＧａＮ自由应变生长、以ＡｌＮ为衬底和以ＧａＮ为衬底等三种不同应变状态下ＡｌＮ／ＧａＮ应变层异质结的价带偏移．着重尝试了能带中含浅ｄ态的情况下，用平均键能方法计算异质结的△Ｅｖ值．由于目前还没有可供比较的实验值或理论计算结果，为检验平均键能方法计算的可靠性，又采用能同时计入各种影响△Ｅｖ因素的较严格的超原胞（ＡｌＮ）ｎ（ＧａＮ）ｎ（００１），（ｎ＝１．３，５）界面自洽计算方法，验证超晶格中平均键能Ｅｍ的“对齐”程度和价带偏移△Ｅｖ的计算结果．

Using average bond energy method,the valence-band offsets of AlN/GaN strained layer heterojunction under three strained conditions(i.e. growing GaN layer on substrate of AlN,growing AlN layer on substrate of GaN and AlN,GaN strained freely to form the heterojunction) are predicted. It is the case that d-band embeds the valence-band when the average bond energy method Was used to determine the band-offsets. For lacking of theorical or experimental data for comparision,we verify our calculation results of valence-band offsets △Ev and the 'alignment' of average bond energy Em in strained layer superlattice (AlN)n (GaN)n(001), (n=1, 3, 5) by supercell self-consistent calculation.