GaAs/Al_xGa_(1-x)As量子阱红外探测器光谱特性的研究

Study on Spectral Characteristic of GaAs/Al_xGa_(1-x)As QWIP

采用MBE法制备了不同结构参数及不同阱中掺杂浓度的GaAs/AlxGa1-xAs量子阱红外探测器外延材料。通过对量子阱红外探测器材料特性和器件特性的实验测试及理论分析,研究了量子阱红外探测器的响应光谱特性,并通过薛定谔方程和泊松方程的求解,对掺杂对量子阱能级的影响做了研究。结果表明,由于应力导致的能带非抛物线性使得阱中能级发生了变化,从而引起吸收峰向高能方向发生了漂移,而阱中进行适度的掺杂没有对量子阱能级造成影响,光致发光谱实验结果与之吻合较好。在光电流谱的实验分析基础之上,分析了量子阱阱宽、Al组分与峰值探测波长λ的关系,为量子阱红外探测器的设计优化提供了参考。

GaAs/AlxGa1-xAs quantum well infrared photodetector （QWIP） materials with different structure parameters and doping concentrations in well were designed and prepared by MBE. The response spectral characteristic of QWIP was studied by experimental test of material and device characteristics. And the effect of doping on QW energy level was studied by solving Schroedinger equation and Poisson equation. Result shows that the change of QW energy level is the reason for peak absorption shifts to higher energy. And the change of Qw energy level is caused by energy band nonparabolicity induced by stress. Moderately doping in well has little effect on QW energy level, and PL result is well corresponded with the theoretic analysis. Basing on the experimental analysis of the photocurrent spectra, the relation between well width, Al content and peak detection wavelengh λp was illuminated, which could provide the reference for the future device design and optimization.