背照射和正照射p-i-n结构GaN紫外探测器的i-GaN和p-GaN厚度设计

摘要

The effects of i-GaN and p-GaN layer thickness on the spectral response of back-illumi-nated and front-illuminated GaN p-i-n structure ultraviolet photodetectors were investigated by theory calculation. For the back-illuminated p-i-n photodetectors, the device quantum efficiency can be im-proved by both suitably decreasing the thickness of i-GaN layer and increasing the thickness of p-GaN layer, and the Ohmic contact property of p-GaN has not obvious influence on the device respon-sivity. The quantum efficiency of photodetector can be improved by reducing the background carrier concentration of i-GaN layer. The results are different for the front-illuminated p-i-n photodetectors. it is found that the device quantum efficiency can be improved by both properly increasing the thick-ness of i-GaN layer and decreasing the thickness of p-GaN layer, and the excellent Ohmic contact property of p-GaN is very important for the front-illuminated p-i-n hotodector. The opposite design method of i-GaN and p-GaN layer for the two photodetectors are mainly attributed to the different en-ergy band and photon absorption.%研究了i-GaN和p-GaN厚度对背照射和正照射p-i-n结构GaN紫外探测器响应光谱的影响。模拟计算发现：对于背照射结构,适当地减小i-GaN厚度有利于提高探测器的响应,降低i-GaN层的本底载流子浓度也有利于提高探测器的响应；p-GaN的欧姆接触特性好坏对探测器的响应影响不大,适当地增加p-GaN厚度可以改善探测器性能。而正照射结构则不同,i-GaN厚度对探测器的响应度影响不大,但欧姆接触特性差将严重降低探测器的响应,适当地减小p-GaN厚度可以大幅度改善探测器的响应特性。能带结构和入射光吸收的差别导致了正照射和背照射探测器结构中i层和p层厚度的选择和设计不同。