Electrical conductivity and carrier concentration control in β-Ga2O3 by Si doping

Electrical conductivity of β-Ga2O3 has been attributed so far to an oxygen deficiency, the donors presumably being oxygen vacancies. This letter shows, however, that the conductivity can be intentionally controlled over three orders of magnitude by Si doping. The related free-carrier concentration, which varies between 1016–1018cm−3, corresponds to a 25%–50% effective Si donors. Since Si is the main impurity present in Ga2O3 powders—in the order of the studied doping levels—we conclude that the electrical conductance of β-Ga2O3 can be attributed to Si impurities, and that the contribution of oxygen vacancies, if any, is not dominant.