Iridium and gold alloy beta gallium oxide expected to achieve p-type conductivity

Abstract

The beta monoclinic gallium oxide (β-Ga2O3) is a wide-bandgap material with promising applications in high-power electronics, but bottleneck problem of p-type conductivity has become the biggest obstacle to device performance improvement. The effective p-type doping can be achieved in β-(Ir x Au y Ga1-x-y )2O3 alloys, promising to be synthesised in the laboratory, from an energy perspective. The β-(Ir x Ga1-x )2O3 exhibits an extended valence band with a maximum of 1.94 eV at the edge of the valence band. The location and bandwidth of the extended valence band can be changed with the Ir concentration. The Au substitution at the Ga(2) site actually creates a relatively shallow level, contrary to the expected deep acceptors. The 2p orbital of the O atom easily coupling with the doped atomic orbital to appear as a hole-polaronic state, while the higher energy of the Au-doped hole state avoids coupling with the valence band maximum of the host material. Theoretical feasibility of p-type doping of β-(Ir x Au y Ga1-x-y )2O3 is achieved.