Enabling visible-light absorption and p-type doping in In2O3 by adding Bi

TL;DR

This paper demonstrates that adding bismuth to In2O3 creates a new valence band enabling p-type doping and enhances visible-light absorption, expanding In2O3's potential applications.

Contribution

The study introduces dilute (In_{1-x}Bi_{x})_2O3} alloys that achieve p-type doping and strong visible-light absorption, a novel modification of In2O3.

Findings

Bi addition raises the valence band energy.

Enhanced optical absorption in the visible spectrum.

Potential for new optoelectronic applications.

Abstract

In2O3 is a prototype wide-band-gap semiconductor that exhibits metallic conductivity when highly doped with Sn while retaining a high degree of transparency to visible light. It is widely used as a transparent window/electrode in solar cells and LEDs. The functionality of In2O3 would be greatly extended if p-type conductivity could also be achieved. Using electronic structure calculations, we show that adding Bi to In2O3, in the form of dilute (In_{1-x}Bi_{x})_2O3} alloys, leads to a new valence band that is sufficiently higher in energy than the original O-2p valence band to allow for p-type doping. Moreover, the raised valence band in the (In_{1-x}Bi_{x})_2O3} dilute alloys leads to strong optical absorption in the visible spectrum, opening up for new applications such as a wide band gap absorber layer in tandem solar cells.