LAUSR

The role of cluster scattering on electron transport properties of ZnMgO/ZnO heterostructures considering three- and five-valley conduction band models was investigated with an ensemble Monte Carlo program developed by us. The cluster scattering is modeled as an elastic collision, in which the electrons confined in ZnO well are scattered by MgZnO clusters. The interface roughness scattering, dislocation scattering, alloy disorder scattering, and phonon scattering are also taken into account in the simulation. For both energy band models, it is found that Mg composition fluctuation ( $\eta $ ), the cluster size ( $\xi $ ), and the 2-D electron gas sheet density (Ns) have a great impact on low-field mobility owing to the cluster scattering. But the low-field mobility of five-valley is slightly smaller than that of three-valley due to the increased total scattering. A further comparison of velocity-field transport characteristics shows that the cluster scattering is prevailing at low temperature, and it significantly decreases the electron drift velocity for both energy band models. Moreover, the threshold electric fields of these two models are both enhanced by approximately 10 kV/cm at 10 K with cluster scatteringconsidered. This paper is beneficial for designing ZnMgO/ZnO heterostructure devices.