Systematic investigation of electrical contact barriers between different electrode metals and layered GeSe

TL;DR

This study systematically investigates the contact barriers between GeSe and various metals, revealing that gold forms the best contact to GeSe's valence band despite not having the highest work function, highlighting interface effects.

Contribution

It provides a detailed analysis of contact barriers between GeSe and six metals, emphasizing the importance of interface chemistry over work function alone.

Findings

Au forms the best contact to GeSe's valence band.

Contact behavior deviates from Schottky-Mott theory.

Interface details significantly influence contact properties.

Abstract

For electronic and photoelectronic devices based on GeSe, an emergent two dimensional monochalcogenide with many exciting properties predicted, good electrical contacts are of great importance for achieving high device performances and exploring the intrinsic physics of GeSe. In this article, we use temperature-dependent transport measurements and thermionic emission theory to systematic investigate the contact-barrier heights between GeSe and six common electrode metals, Al, Ag, Ti, Au, Pt and Pd. These metals cover a wide range of work functions (from ~ 3.6 eV to ~ 5.7 eV). Our study indicates that Au forms the best contact to the valence band of GeSe, even though Au does not possess the highest work function among the metals studied. This behavior clearly deviates from the expectation of Schottky-Mott theory and indicates the importance of the details at the interfaces between metals and GeSe.