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采用分子束外延(MBE)技术,在GaSb衬底上生长了pin结构的InAs(8ML)/GaSb(8ML)超晶格中波红外光电二极管。经过(NH4)2S表面钝化后的Ⅳ特性曲线表明:低的正偏压下,理想因子n在2左右,势垒区的复合电流起主要作用;偏压超过0.14 V时,n在1左右,少子扩散电流占主。表面势垒区中过多的Ⅲ族元素的空位缺陷导致表面出现大量复合中心。采用阳极硫化后,表面漏电大大减小,反偏漏电流密度降低三个数量级,零偏阻抗R0达到106欧姆,R0A达到103量级。
A pin-structured InAs (8ML) / GaSb (8ML) superlattice medium wave infrared photodiode was grown on GaSb substrate by molecular beam epitaxy (MBE). The IV characteristic curve after passivation of (NH4) 2S shows that under the low positive bias voltage, the ideal factor n is about 2, and the recombination current in the barrier region plays a major role. When the bias voltage exceeds 0.14 V, n is about 1 , Less child diffusion current dominated. The vacancy defects of the superfluous Group III elements in the surface barrier zone lead to a large number of recombination centers on the surface. After the anodic vulcanization, the surface leakage is greatly reduced, the reverse bias leakage current density is reduced by three orders of magnitude, the bias impedance R0 reaches 106 ohms, and the R0A reaches 103 orders of magnitude.