Physical understanding of the Hooge parameter in ZnO nanowire devices

Abstract

In this paper, we propose a random walk model as the main generation. mechanism for low-frequency noise in ZnO nanorod structures where surface states are involved. In this model, electrons in the channel can be trapped at surface states and perform a random walk between different surface states before being detrapped into the channel, in this model. Analytic expressions for the spectral noise density and the Hooge parameter are derived and applied to analyze the experimental results on back-gate ZnO-nanorod field-effect transistors from the literature. An analysis using this model provided quantitative information on the surface states in different atmospheric conditions. According to the model, the Hooge parameter is a function of the temperature, carrier concentration, the size of the nanorod and the surface states density and in particular, is inversely proportional to the radius of the nanorod. This model can be utilized in the analysis of low-frequency noise in other types of nanorod devices.