Native defects and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mi>p</mml:mi> </mml:math> -type dopability in transparent <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mi>β</mml:mi> </mml:math> - <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>Te</mml:mi> <mml:mi mathvariant="normal">O</mml:mi> </mml:mrow> <mml:mn>2</mml:mn> </mml:msub> </mml:math> : A first-principles study

Abstract

Although $\ensuremath{\beta}$-${\mathrm{Te}\mathrm{O}}_{2}$ is a promising $p$-type transparent conducting oxide, due to a large optical gap ($\ensuremath{\sim}3.7$ eV) and a light effective hole mass, its hole dopability still remains unexplored. In this work, the electronic structure of $\ensuremath{\beta}$-${\mathrm{Te}\mathrm{O}}_{2}$ and its point defects are investigated using the HSEsol functional with the band-gap-tuned mixing parameter. Our calculations reveal that $\ensuremath{\beta}$-${\mathrm{Te}\mathrm{O}}_{2}$ 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 $\ensuremath{\beta}$-${\mathrm{Te}\mathrm{O}}_{2}$ is intrinsically an insulator. From systematic calculations of the trivalent dopants, as well as hydrogen, $\mathrm{Bi}$ doping is suggested as the best candidate for an acceptor dopant. This work paves the way for the material design of $p$-type $\ensuremath{\beta}$-${\mathrm{Te}\mathrm{O}}_{2}$.

Topics & Concepts