An analysis of the Mott-Schottky behavior in ZnO-Bi2O3 based varistors

A series of non-converging frequency-dependent Mott–Schottky straight lines can lead to significant errors in the calculation of the device-related parameters (such as; built-in-potential, barrier height, carrier concentration, etc.) for the ZnO-Bi2O3 based varistors. These errors are illustrated using the frequency-dependent slope of these straight lines. To avoid this problem, a method of obtaining the frequency-independent Mott-Schottky response has been devised for these devices. This method employs the well-known lumped parameter/complex plane analysis technique, and thereby resolves the complexity of the frequency-dependent Mott–Schottky response. Using this technique, it is possible to characterize the Mott–Schottky behavior of varistor materials without incorporating frequency-dependent phenomenon in the analysis. These parameters are self-consistent, and satisfy the basic/classical Mott-Schottky equation.