Interfacial electronic properties between PtSe2and 2D metal electrodes: a first-principles simulation

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.