Theoretical insights for Improving the Schottky-barrier Height at the Ga$_2$O$_3$/Pt Interface

TL;DR

This study uses atomic structure modeling and electronic calculations to analyze how water contamination affects the Schottky barrier height at the Ga$_2$O$_3$/Pt interface, revealing potential for optimizing device interfaces.

Contribution

It provides the first detailed atomic-level analysis of water's impact on SBH at the Ga$_2$O$_3$/Pt interface using hybrid density functional theory.

Findings

Water contamination can significantly lower SBH from ~2 eV to near zero.

Interface orientation has minimal effect on SBH.

Proper substrate preparation can maintain high SBH by reducing water adsorption.

Abstract

In this work we study the Schottky barrier height (SBH) at the junction between $\beta$-Ga$_2$O$_3$ and platinum, a system of great importance for the next generation of high-power and high-temperature electronic devices. Specifically, we obtain interfacial atomic structures at different orientations using our structure matching algorithm and compute their SBH using electronic structure calculations based on hybrid density functional theory. The orientation and strain of platinum are found to have little impact on the barrier height. In contrast, we find that decomposed water (H.OH), which could be present at the interface from Ga$_2$O$_3$ substrate preparation, has a strong influence on the SBH, in particular in the ($\overline{2}$01) orientation. The SBH can range from $\sim$2 eV for the pristine interface to nearly zero for the full H.OH coverage. This result suggests that SBH of $\sim$2~eV can be achieved for the Ga$_2$O$_3$($\overline{2}$01)/Pt junction using the substrate preparation methods that can reduce the amount of adsorbed water at the interface.