Assessing the potential of Mg-doped Cr₂O₃ as a novel p-type transparent conducting oxide

One of the current challenges faced by material scientists is the development of a p-type transparent conducting oxide with levels of optical transparency and electronic conductivity to equal those of the universally n-type industry leaders such as Sn-doped In₂O₃. The discovery of a p-type analogue would allow for the combination of both polarities into a heterojunction, accessing the potential for transparent electronics. In this study, an insulating material, Cr₂O₃, is investigated both experimentally and computationally to determine if it is a viable p-type host matrix as has been recently proposed in the literature. The geometric and electronic structure are examined by high resolution x-ray diffraction, x-ray photoelectron spectroscopy, and periodic density functional theory (specifically, PBE + U). By incorporating Mg and performing a comprehensive defect analysis, the dominant intrinsic and extrinsic carriers in the material are determined, and it is shown that Cr₂O₃ has the potential to display p-type conductivity when appropriately doped.