基于运算放大器和傅里叶谱分析的电导与微分电导同步测量

摘要

We propose a method to measure conductance and differential conductance simultaneously using an operational amplifier and Fourier spectrum analyzer. Theoretical analysis is conducted to study the output voltage characteristics of a nonlinear diode under AC and DC bias. Assuming that high-frequency contents are much smaller than low-frequency components in that output voltage, a measurement equation for conductance and differential conductance of the diode is derived. And, an analytical expression of the physical relationship is presented. Simulation and experiments show validity of the method. We also find that the differential conductance signal is an order of magnitude stronger than the conductance signal when the diode is under the same DC bias.%提出一种基于运算放大器和傅里叶谱分析仪的电导与微分电导同步测量方法.针对非线性样品二极管在交直流偏压作用下的输出响应电压特征进行了理论研究,在输出响应电压信号谐波高频成分远小于低频成分的假设条件下,推导了二极管电导及微分电导同步测量方程,得到完整的物理关系解析表达式.对二极管进行的仿真实验和电路测量实验结果验证了该方法的有效性；并发现二极管在相司的直流偏压下,其微分电导信号的精度比电导信号的精度高一个量级.