GaN/AlN半导体异质结带阶超原胞法计算

为了对GaN/AlN异质结电子结构有更为深入的认识,采用超原胞模型,对其进行了基于密度泛函理论的第一性原理计算.结果发现GaN/AlN为突变同型异质结,价带顶带阶为0.62eV,与实验值很接近.通过使用常用的平均键能法、平均势法和芯态法三种近似方法对GaN/AlN带阶的计算,比较得出,超原胞法虽然计算量较大,但能够给出异质结界面附近更为详细的信息,这一点其他三种近似方法无法得到,但他们也能够得出与实验值基本一致的带阶参量.

Super Cell Calculation of GaN/AlN Semiconductor Heterojunction Valence-band Offsets

In order to understand the electronic structure of GaN/AlN heterojunction deeply,it is calculated by the density functional theory based on the first principle plane wave pseudopotential method,via the super cell model.The direct calculation of the GaN/AlN super cell demonstrates that the GaN/AlN heterojunction is homotype and changes abruptly at the interface,besides,the valence-band offsets of GaN/AlN is 0.62 eV,which is very close to the experimental result.Additionally,it can be concluded that the super cell calculation has more advantages than the other common indirect calculation of heterojunction band offsets,such as the average bond energy,the average potential and the core state.The super cell calculation supplies more information of the GaN/AlN heterojunction interface while the reference energy band methods can not.Nevertheless,band-offsets parameters obtained by the other indirect methods are also reasonable compared with the experimental value.