Native defects andp-type dopability in transparent β-TeO 2: A first-principles study

Although /3-TeO2 is a promising p-type transparent conducting oxide, due to a large optical gap (similar to 3.7 eV) and a light effective hole mass, its hole dopability still remains unexplored. In this work, the electronic structure of /3-TeO2 and its point defects are investigated using the HSEsol functional with the band-gap-tuned mixing parameter. Our calculations reveal that /3-TeO2 exhibits a significant difference between the fundamental and optical band gaps because lower-energy optical transitions are dipole forbidden. Additionally, it has a low hole effective mass, especially in plane. The point-defect calculations show that /3-TeO2 is intrinsically an insulator. From systematic calculations of the trivalent dopants, as well as hydrogen, Bi doping is suggested as the best candidate for an acceptor dopant. This work paves the way for the material design of p-type /3-TeO2.