Controlled bipolar doping in Cu3N (100) thin films

Abstract

We have fabricated insulating, p- and n-type Cu3N(100) films on SrTiO3(100) by plasma assisted molecular beam epitaxy. By controlling the Cu/N flux rate, p-type doping with 1018-1020cm-3 in Cu-poor condition and n-type doping with 1019-1020cm-3 in N-poor condition were obtained without introducing foreign species. Together with formation of insulating Cu3N films with an optical absorption coefficient of ∼105cm-1 in the photon energy above ∼2.2eV and an estimated indirect bandgap of ∼1.3eV, the bipolar doping in Cu3N films would be promising for solar energy conversion applications.