Analysis of Electrical Transport Properties of Amorphous Oxide Semiconductors by an Extended Percolation-Based Random Band-Edge Model

Abstract

We investigate the electrical transport in amorphous oxide semiconductors by applying the percolation-based random band-edge model proposed by Nenashev et al. [Phys. Rev. B 100, 125202 (2019)] to multicationic, multianionic, and multinary materials. We modify the model by introducing the Hall-scattering factor. This allows us to evaluate, besides the conductivity, the temperature-dependent free charge-carrier concentration and Hall mobility, additionally enabling the inclusion of localized tail states in the model. The extended model allows analysis of pulsed-laser deposited amorphous zinc tin oxide, magnetron-sputtered amorphous zinc oxynitride, and zinc magnesium oxynitride thin films with carrier concentrations ranging from ${10}^{16}$ to ${10}^{19}\phantom{\rule{0.2em}{0ex}}{\mathrm{cm}}^{\ensuremath{-}3}$ at room temperature. Excellent agreement of the extended model data with the measured electrical properties is found for the investigated temperature regime of $50$ to $300\phantom{\rule{0.2em}{0ex}}\mathrm{K}$. In addition, we extract critical parameters of the random band-edge model and discuss them with regard to varying deposition parameters and different anion and cation concentrations. In particular, we find the standard deviation of the mobility edge distribution to be ranging between $20$ and $60\phantom{\rule{0.2em}{0ex}}\mathrm{meV}$ for the investigated materials.