Theoretical Insights for Improving the Schottky-Barrier Height at the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:msub><mml:mi>Ga</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mn>3</mml:mn></mml:msub><mml:mrow><mml:mo>/</mml:mo><mml:mi>Pt</mml:mi></mml:mrow></mml:math> Interface
Félix Therrien, Andriy Zakutayev, Vladan Stevanović
Abstract
In this work, we study the Schottky-barrier height (SBH) at the junction between $\ensuremath{\beta}$-${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ 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 molecules ($\mathrm{H}$.$\mathrm{OH}$), which could be present at the interface from ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}$ substrate preparation, has a strong influence on the SBH, in particular in the ($\overline{2}01$) orientation. The SBH can range from approximately $2$ eV for a pristine interface to nearly zero for a full $\mathrm{H}$.$\mathrm{OH}$ coverage. This result suggests that a SBH of approximately $2$ eV can be achieved for the ${\mathrm{Ga}}_{2}{\mathrm{O}}_{3}(\overline{2}01)/\mathrm{Pt}$ junction using the substrate-preparation methods that can reduce the amount of adsorbed water at the interface.