采用基于第一性原理计算的平面波超软赝势方法, 计算电子辐照后由简单缺陷引起的GaN外延材料的光学性能变化。首先计算出本征GaN晶体的性质作为研究缺陷性质变化的参照, 着重分析了VN、VGa、GaN、MgGa、MgGa-ON、MgGa-VN、VGa-ON等缺陷对光吸收谱的影响。由于InGaN多量子阱是主要的LED发光来源, 还对不同In摩尔分数掺杂下的GaN进行了光学性质研究。结果表明: VN、GaN和In掺杂等缺陷使GaN主吸收峰出现红移且吸收系数均降低; 而VGa、MgGa、MgGa-ON、VGa-ON均使GaN的主吸收峰出现蓝移, 只是MgGa缺陷使主吸收峰峰值增加, 其余缺陷均使主峰吸收系数降低; MgGa-VN仅仅减小了主峰峰值, 并未改变光子吸收波长。研究结果表明, 电子辐照后的缺陷会使材料性能发生变化。

The plane wave ultra soft pseudo potential method based on the first principle is used to calculate the optical properties of GaN epitaxial materials caused by point defects after electron irradiation. First, the properties of the intrinsic GaN crystal are calculated as a reference for the study of the variation of the defect properties. The effects of the defects of VN, VGa, GaN, MgGa, MgGa-ON, MgGa-VN, VGa-ON on the optical absorption spectra are emphatically analyzed. As the InGaN multi quantum well is the main source of LED emission, the optical properties of GaN doped with different In mole fraction are also studied. The results show that VN, GaN and doing of In make the GaN absorption peak red shift and the absorption coefficient decreases. VGa, MgGa, MgGa-ON, VGa-ON all make the main absorption peaks of GaN appear blue shift. MgGa defect makes the main absorption peaks value increase, and the remaining defects make the main peak absorption coefficient decrease. MgGa-VN only decreases the main peak value, does not change the photon absorption wavelength. It is confirmed that the defects can make the material properties change after electron irradiation.