Interfacial electronic properties between PtSe2 and 2D metal electrodes: a first-principles simulation

Abstract

Monolayer (ML) PtSe₂ is a two-dimensional (2D) semiconductor with a modest band gap and high carrier mobility, and it is a promising 2D material for electronic devices. Finding suitable metal electrodes is a key factor in fabricating high-performance PtSe₂ field effect transistors (FETs). In this study, a series of 2D metals, transition metal dichalcogenides (NbSe₂, TaS₂), borophene, and MXenes (V₂C(OH)₂, V₂CF₂, Nb₂C(OH)₂, Nb₂CF₂, Nb₂CO₂, Hf₂C(OH)₂, Hf₂CF₂) were used as electrodes for FET fabrication. The interfacial electronic properties of electrodes and PtSe₂ were studied in both the vertical and lateral directions using the ab initio method. In the vertical direction, PtSe₂ formed ohmic contacts with most of the 2D metals except for Nb₂CF₂ and Hf₂CF₂. Specifically, in the cases of Nb₂CF₂ and Hf₂CF₂, p- and n-type Schottky contacts were formed with Schottky barrier heights (SBHs) of 0.48 eV and 0.02 eV, respectively. In the lateral direction, PtSe₂ with contacting Hf₂CF₂ and V₂C(OH)₂ electrodes formed n-type Schottky contacts with SBHs of 0.14 eV and 0.09 eV, respectively. In the cases of TaS₂ and Nb₂CF₂ electrodes, p-type Schottky contacts with SBHs of 0.35 eV and 0.29 eV, respectively, were formed. Moreover, n-type ohmic contacts were observed when Hf₂C(OH)₂ and Nb₂C(OH)₂ electrodes were applied, and p-type ohmic contacts were formed when borophene, NbSe₂, Nb₂CO₂, and V₂CF₂ electrodes were used. This work reports a systematic investigation of ML PtSe₂-2D metal interfaces and serves as a practical guide for selecting electrode materials for PtSe₂ FETs.