【摘要】 利用正向交流(AC)小信号方法对发光二极管(LED)的电容-电压特性进行测量,可以观察到发光二极管中的负电容现象.提出了测量到的负电容现象是表象,不存在负电容;发光二极管p-n结的结电容在特定的正向电压范围内等效于可变电容.分析可变电容对交流小信号响应得到:特定参数的可变电容使电流的相位移相π,使得在测量中表现为负电容;得到了发光二极管负电容与角频率的关系表达式.更多还原

【Abstract】 Using the forward alternating current (ac) small signal method to measure the capacitance-voltage characteristic of an LED, negative capacitance can be observed.We propose that this phenomenon is a surface phenomenon, and there is no real negative capacitance.We further propose that the capacitance of the p-n junction in an LED is equivalent to the variable capacitance in a certain range of forward voltage.By the corresponding analysis of variable capacitance to the alternating current small signal, we find that the variable capacitance for certain parameters can shift the phase of the current by π,leading to negative capacitance in measurement.Additionally, an expression for the negative capacitance in an LED that relates it to the rotational frequency is obtained for the first time.更多还原