Interface Dipole and Band Bending in Hybrid p-n Heterojunction MoS2/GaN(0001)

TL;DR

This study investigates the electronic properties of a hybrid MoS2/GaN heterostructure, revealing charge transfer, interface dipole formation, and band offset details crucial for nanoelectronic device engineering.

Contribution

It provides detailed experimental insights into the electronic structure and interface phenomena of MoS2/GaN heterostructures using ARPES and HR-XPS.

Findings

Charge transfer from MoS2 to GaN observed

Interface dipole of 0.2 eV identified

Valence and conduction band offsets quantified

Abstract

Hybrid heterostructures based on bulk GaN and two-dimensional (2D) materials offer novel paths toward nanoelectronic devices with engineered features. Here, we study the electronic properties of a mixed-dimensional heterostructure composed of intrinsic n-doped MoS2 flakes transferred on p-doped GaN(0001) layers. Based on angle-resolved photoemission spectroscopy (ARPES) and high resolution X-ray photoemission spectroscopy (HR-XPS), we investigate the electronic structure modification induced by the interlayer interactions in MoS2/GaN heterostructure. In particular, a shift of the valence band with respect to the Fermi level for MoS2/GaN heterostructure is observed; which is the signature of a charge transfer from the 2D monolayer MoS2 to GaN. ARPES and HR-XPS revealed an interface dipole associated with local charge transfer from the GaN layer to the MoS2 monolayer. Valence and conduction band offsets between MoS2 and GaN are determined to be 0.77 and -0.51 eV, respectively. Based on the measured work functions and band bendings, we establish the formation of an interface dipole between GaN and MoS2 of 0.2 eV.