Two-dimensional electron transport in MgZnO/ZnO heterostructures: role of interface roughness

Abstract

Mobility of two-dimensional electron gases in MgZnO/ZnO heterostructures with interface roughness effects was investigated theoretically using path-integral framework. We modelled the roughness-induced fluctuation by including two major effects, i.e. the electron and polarization-induced positive charge concentrations. We showed that both effects cause the scattering potential in the in-plane direction and hence affect the 2D mobility. In this work, we treated both electron and polarization-induced positive charge concentrations as equally important factors and then calculated the electron mobility and compared with the experimental result of Mg0.2Zn0.8O/ZnO heterostructure at high-electron concentrations. We found that the fitting parameters Δ = 0.26 nm, Λ = 2.5 nm gave good description to the mobility data. We also showed that neglecting the polarization-induced positive charge concentration led to overestimating the 2D mobility.