作为常见的高迁移率直接带隙半导体, 砷化镓 (gallium arsenide, GaAs) 的光电响应性质一直是学界研究的焦点. 针对特殊结构半导体器件的光电响应方式理论上研究一般采用宏观有限元方法结合半经典理论的模拟. 随着器件尺寸的小型化, 微观结构的重要性更加凸显. 通过非平衡态格林函数结合密度泛函理论方法 (non-equilibrium Green’s function method with density functional theory, NEDF-DFT) 首次在原子尺度下计算了砷化镓纳米结在化学掺杂和栅极下的光响应, 定性分析了材料掺杂浓度对光响应的影响. 本工作对于半导体器件光电性质的模拟分析方法的拓展和器件性能的定性理解具有比较重要的意义.

As a direct bandgap semiconductor with high electron mobility, GaAs and its photoelectric response have been the focus of academic researches. Macroscopic finite element methods combined with semi-classical theory are normally used to simulate the photoelectric response of semiconductor devices with specific structures. With the miniaturization of devices, the microscopic structural features become more important. In this paper, the non-equilibrium Green’s function method with density functional theory(NEGF-DFT) was firstly adopted to calculate the light response of GaAs nanojunctions under chemical doping and gate voltage, and qualitative analysis of the doping density on light response is achieved. This work casts light on the first-principle analysis of photoelectric response of semiconductor devices and will be meaningful to the future researches in this field.