Nanoscale probing of surface potential landscape at MoS2/BP van der Waals p-n heterojunction

Nanotechnology. 2022 Dec 16;34(9). doi: 10.1088/1361-6528/aca61a.

Abstract

2D van der Waals heterostructure paves a path towards next generation semiconductor junctions for nanoelectronics devices in the post silicon era. Probing the band alignment at a real condition of such 2D contacts and experimental determination of its junction parameters is necessary to comprehend the charge diffusion and transport through such 2D nano-junctions. Here, we demonstrate the formation of the p-n junction at the MoS2/Black phosphorene (BP) interface and conduct a nanoscale investigation to experimentally measure the band alignment at real conditions by means of measuring the spatial distribution of built-in potential, built-in electric field, and depletion width using the Kelvin probe force microscopy (KPFM) technique. We show that optimization of lift scan height is critical for defining the depletion region of MoS2/BP with nanoscale precision using the KPFM technique. The variations in the built-in potential and built-in electric field with varying thicknesses of MoS2are revealed and calibrated.

Keywords: Kelvin probe force microscopy; MoS2/BP heterostructure; built-in electric field; built-in potential; depletion width; p–n junction.