Investigation of Hole Dopability in Oxygen-2p-Dominated Bands

High Resolution Image Download MS PowerPoint Slide The development of p-type oxide semiconductors remains impeded by the inherently low-lying valence-band maximum (VBM) dominated by O 2p states. A prevailing approach to mitigate this limitation is to elevate the VBM by introducing cation states that hybridize with O 2p orbitals or lie energetically above the O 2p level. Nevertheless, the p-type oxides reported to date exhibit limited hole mobilities. To expand the search space, it is essential to accurately understand the intrinsic difficulty of introducing holes into O-2p-dominated bands. Accordingly, we evaluated 845 oxides to identify those in which holes can be doped into O-2p-dominated bands. Our high-throughput screening revealed CaCdO 2 as the only promising exemplar, in which the VBM is slightly hybridized with deep-lying Cd 3d states. Our screening suggests that hole doping into O-2p-dominated bands is extremely difficult and thus reinforces the effectiveness of the traditional “VBM-raising strategy”.