Impact of Mg content on native point defects in MgxZn1-xO (0 ≤ x ≤ 0.56)

We used depth-resolved cathodoluminescence spectroscopy and surface photovoltage spectroscopy to measure the densities, energy levels, and spatial distributions of zinc/magnesium cation and oxygen vacancies in isostructural, single-phase, non-polar MgxZn1-xO alloys over a wide (0 ≤ x ≤ 0.56) range. Within this wide range, both defect types exhibit strong Mg content-dependent surface segregation and pronounced bulk density minima corresponding to unit cell volume minima, which can inhibit defect formation due to electrostatic repulsion. Mg in ZnO significantly reduces native defect densities and their non-polar surface segregation, both major factors in carrier transport and doping of these oxide semiconductorsThe authors gratefully acknowledge National Science Foundation, Grant No. DMR-1305193 (Charles Ying and HaiyanWang), for support of this work.W.W. acknowledges partial funding from the Center for Emergent Materials, an NSF MRSEC (DMR 1420451) and AFOSR, Award # FA9550-14-1-0322. A.R.-C. acknowledges Juan de la Cierva program under Contract No. JCI-2012-14509 (Spain