High-electron-affinity oxide V2O5 enhances surface transfer doping on hydrogen-terminated diamond

Diamond exhibits many desirable properties that could benefit the development of future carbon-based electronic devices. Its hydrogen-terminated surface, in conjunction with a suitable surface acceptor, develops a two-dimensional (2D) p-type surface conductivity through the surface transfer doping mechanism which can then be harvested for constructing functional devices. In this study, we have revisited the surface transfer doping of diamond by a high electron affinity (EA) transition metal oxide, V2O5. Through a combination of in-situ electrical measurements, Hall effect measurements and first-principles density functional theory (DFT) calculations, we explicitly show the intrinsic surface transfer doping behavior of V2O5, with doping performance superior to other competing TMOs such as MoO3. The metallic surface conduction of diamond induced by V2O5 is persistent down to 250 mK; this when coupled with the high hole density exceeding 7 x 10(13) cm(-2) offers a promising platform for the development of advanced diamond surface electronics exploiting many interesting quantum transport properties of the 2D hole layer of diamond.