用从头计算方法总能理论研究了6H—SiC(0001)(√3×√3)R30°衬底上生长的GaN薄膜的界面结构特性.计算结果表明:GaN膜为Ga极性的纤锌矿结构;6H—SiC(0001)衬底表面台阶引起的GaN岛合并在薄膜中产生边界堆垛失配(SMBs),而这种SMBs缺陷随着薄膜生长厚度的增加可以消除.
Ab initio total energy calculations are performed to determine the interface structure of GaN films grown on the 6H-SiC(0001) (√3×√3)R30° substrate. The results show that the GaN film is of the wurtzite structure and has the Ga-polarity. It is also shown that stacking mismatch boundaries (SMBs) caused by the coalescence of GaN islands grown on stepped terraces of the 6H--SiC(0001) surface may be removed by stacking faults as the _ lm grows.