Chemical manipulation of hydrogen induced high p-type and n-type conductivity in Ga2O3

TL;DR

This paper demonstrates a novel hydrogen-based method to reversibly induce high p-type and n-type conductivity in Ga2O3, a wide band gap semiconductor, enabling new device applications.

Contribution

It introduces a new hydrogen manipulation technique to achieve tunable, reversible, and high conductivity types in Ga2O3 without additional doping.

Findings

Hydrogen induces a 9-order magnitude increase in n-type conductivity.

Conductivity can be switched to p-type by altering hydrogen incorporation.

Density functional theory and positron annihilation spectroscopy confirm hydrogen's role in conductivity modulation.

Abstract

Advancement of optoelectronic and high-power devices is tied to the development of wide band gap materials with excellent transport properties. However, bipolar doping (n-type and p-type doping) and realizing high carrier density while maintaining good mobility have been big challenges in wide band gap materials. Here P-type and n-type conductivity was introduced in beta-Ga2O3, an ultra-wide band gap oxide, by controlling hydrogen incorporation in the lattice without further doping. Hydrogen induced a 9-order of magnitude increase of n-type conductivity with donor ionization energy of 20 meV and resistivity of 10-4 Ohm.cm. The conductivity was switched to p-type with acceptor ionization energy of 42 meV by altering hydrogen incorporation in the lattice. Density functional theory calculations were used to examine hydrogen location in the Ga2O3 lattice and identified a new donor type as the source of this remarkable n-type conductivity. Positron annihilation spectroscopy confirmed this finding and the interpretation of the results. This work illustrates a new approach that allows a tunable and reversible way of modifying the conductivity of semiconductors and it is expected to have profound implications on semiconductor field. At the same time it demonstrates for the first time p-type and remarkable n-type conductivity in Ga2O3 which should usher in the development of Ga2O3 devices and advance optoelectronics and high-power devices