发光二极管的低频电容特性

Low frequency capacitance characteristics of light-emitting diodes

通过自建装置精确测试了发光二极管(LED)的低频(小于102Hz)电学特性。电学测量表明,所有LED在低频下都表现出明显的负电容(NC)现象,且频率越低NC现象越明显。调制发光测量表明,相对发光强度在低频下表现出明显饱和现象,并且随频率增加而减小。比较电学和光学的测量结果可以证实,辐射发光是产生NC现象的主要原因。通过对LED电学测量结果的详细分析得出了NC随电压和频率的变化关系式。

Low frequency （〈10^2 Hz） electrical characteristics of light-emitting diodes（LEDs） are accurately measured by the self-built-up device.All measured diodes display obvious negative capacitance（NC） at low frequency,and the lower the frequency,the stronger the NC is.At low frequencies,the saturation of the relative-luminescence intensity is observed in the voltage modulation luminescence,and its value decreases with the frequency increase.The comparison of the electrical property with the optical one for LEDs confirms that the radiation luminescence is the main reason that causes negative capacitance in LEDs.In the end,the expression of negative capacitance is obtained based on the the electrical measurement results.