Electrical characterization of structured platinum diselenide devices

TL;DR

This study investigates the electrical properties of platinum diselenide (PtSe2), focusing on contact engineering, thickness-dependent transport, and edge contact improvements to advance 2D TMD-based nanoelectronics.

Contribution

It provides a comprehensive analysis of contact resistivity, sheet resistance, and the effects of nanostructuring on contact performance in PtSe2 devices.

Findings

Contact resistivity varies with contact metal and film thickness.

Edge contacts significantly reduce contact resistivity by up to 70%.

Electrical characterization confirms the semimetal to semiconductor transition.

Abstract

Platinum diselenide (PtSe2) is an exciting new member of the two-dimensional (2D) transition metal dichalcogenide (TMD) family. it has a semimetal to semiconductor transition when approaching monolayer thickness and has already shown significant potential for use in device applications. Notably, PtSe2 can be grown at low temperature making it potentially suitable for industrial usage. Here, we address thickness dependent transport properties and investigate electrical contacts to PtSe2, a crucial and universal element of TMD-based electronic devices. PtSe2 films have been synthesized at various thicknesses and structured to allow contact engineering and the accurate extraction of electrical properties. Contact resistivity and sheet resistance extracted from transmission line method (TLM) measurements are compared for different contact metals and different PtSe2 film thicknesses. Furthermore, the transition from semimetal to semiconductor in PtSe2 has been indirectly verified by electrical characterization of field-effect devices. Finally, the influence of edge contacts at the metal - PtSe2 interface has been studied by nanostructuring the contact area using electron beam lithography. By increasing the edge contact length, the contact resistivity was improved by up to 70% compared to devices with conventional top contacts. The results presented here represent crucial steps towards realizing high-performance nanoelectronic devices based on group-10 TMDs.