Functionalized Sc₂N as Ohmic-contact electrodes for monolayer PtSe₂: an ab initio study

Functionalized Sc₂N monolayers are potential ideal electrodes for two-dimensional semiconductors owing to their broad scope of work functions and smooth surfaces. We studied the possibility of functionalized Sc₂N as Ohmic-contact electrodes for monolayer (ML) PtSe₂ Schottky barrier field-effect transistors (SBFETs) and simulated the device performances from an ab initio study. The surface functionalization of Sc₂N weakened the interface coupling with ML PtSe₂. The bands from each component of the PtSe₂/Sc₂NF₂ and PtSe₂/Sc₂N(OH)₂ vertical heterostructures were almost maintained, and n-type Ohmic contacts were found in both the vertical and lateral interfaces. The valence bands of the PtSe₂/Sc₂NO₂ vertical heterostructure showed apparent hybridization, and a p-type Ohmic contact was found in the lateral interface. Particularly, the n-type ML PtSe₂ SBFET with Sc₂N(OH)₂ electrodes possessed a near-ideal subthreshold swing (62 mV dec^-1) and surpassed the high-performance target of the International Roadmap for devices and systems for the year 2037 in terms of on-state current (1166 vs. 790 μA μm^-1), delay time (0.41 vs. 0.84 ps), and power dissipation (0.24 vs. 0.40 fJ μm^-1).