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对Ga面p型GaN/Al0·35Ga0·65N/GaN应变异质结构中形成的二维空穴气(2DHG)进行了研究.首先基于半导体-绝缘体-半导体异质结构模型确定了应变异质中的临界厚度,然后自洽求解薛定谔方程和泊松方程,计算了当中间势垒层AlGaN处于完全应变状态和半应变状态两种条件下,顶层GaN及中间层AlGaN厚度的变化对2DHG分布的影响.计算结果表明,势垒层AlGaN和顶层GaN的应变状态和厚度对极化引起的2DHG面密度及分布有重要影响.在此基础上制备了p型GaN/Al0·35Ga0·65N/GaN应变量子阱结构肖特基器件,并通过器件的C-V测试证实了异质结处2DHG的存在.器件响应光谱的测试结果表明,由于p型GaN/Al0·35Ga0·65N/GaN量子阱中强烈的极化作用和Stark效应使得器件零偏压和反向偏压时的响应光谱都向短波方向移动了10nm,在零偏压下器件在280nm处的峰值响应为0·022A/W,在反向偏压为1V时,峰值响应达到0·19A/W,已经接近理论值.
Two-dimensional hole gas (2DHG) formed in the Ga-p-type GaN / Al0.35Ga0.65N / GaN strained heterostructure was studied.Firstly, based on the semiconductor-insulator-semiconductor heterostructure model, Then, the Schrödinger equation and the Poisson equation were solved in a self-consistent manner. The influence of AlGaN thickness on the distribution of 2DHG was calculated when the AlGaN in the middle barrier layer was in the fully-strain state and the semi-strain state. The calculated results show that the strain state and thickness of AlGaN and GaN on the top of the barrier layer have an important effect on the density and distribution of 2DHG induced by polarization, and a p-type GaN / Al0.35Ga0.65N / GaN strained quantum well Structure Schottky device and confirmed the existence of 2DHG at the heterojunction by the CV test of the device.The test results of the device response spectrum show that due to the strong polarization in the p-type GaN / Al0.35Ga0.65N / GaN quantum well And Stark effect make the response spectrum of the device at zero bias and reverse bias shift to 10nm in the shortwave direction. The peak response of the device under zero bias at 280nm is 0.022A / W, and at the reverse bias voltage of At 1V, the peak response reaches 0 · 19A / W, yes Close to the theoretical value.