发光二极管的反偏电容和电导特性研究  

Reverse-biased capacitance and conductance characteristics for lighting emitting diodes

作　　者：程星福 刘显明[1] 陈伟民[1] 赖伟[1] 雷小华[1] 

机构地区：[1]重庆大学光电工程学院 光电技术及系统教育部重点实验室,重庆400044

出　　处：《光电子．激光》2014年第4期648-652,共5页Journal of Optoelectronics·Laser

基　　金：国家“863”计划(2013AA03A118);重庆市自然科学基金(CSTC2011BA7023);中国博士后科学基金资助项目

摘　　要：发光二极管(LED)在反向偏压工作状态下的电学特性在一定程度上反映PN结中载流子的传输特性。本文对反偏状态下LED的电容电导特性进行了研究,通过在直流偏置上叠加交流小信号,得到了LED反偏电容和电导随频率变化的关系。实验结果表明,随着频率的增加,LED反偏电容减小,反偏电导增加。不同I-V特性的LED具有明显不同的反偏电容电导特性。分析认为,PN结的隧穿电流和表面漏电流是引起以上现象的主因;反偏电容和电导特性可作为对LED评价的重要参数指标,实现产品质量筛选。The electrical characteristics of light emitting diode （LED） in the reverse-biased state are very important,which ean reflect the transport properties of carriers in the PN junction. In this paper, the ca padtanee and conductance characteristics of LED samples in the reverse-biased state are studied in experiment and theory. The capacitance and conductance as a function of modulation frequency are obtained experimentally by adding a small alternating current （AC） signal on a direct current （DC） bias voltage. Experimental results show that the capacitance decreases and the conductance increases with the increas ing modulation frequency for reverse-biased LED samples. For LEDs with different I-V characteristics, the reverse-biased capacitance and conductance characteristics are different obviously,even for the samples with similar I-V characteristics in the forward biased state. This means that the parameters in the reverse-biased state for LED samples are associated with their properties in the forward-biased state when working in the normal conditions. Analysis suggests that the reverse-biased capacitance and con ductance characteristics mainly result from the tunneling current and surface leakage current. Thus, the reverse-biased capacitance and conductance characteristics can be useful parameters to evaluate the per formance of light emitting diodes.

关 键 词：发光二极管(I ED) 反偏电容 反偏电导 隧穿电流 

分 类 号：TN312.8[电子电信—物理电子学]