# Molecular Beam Epitaxy of 2H-TaS$_2$ few-layers on GaN(0001)

## TL;DR

This study demonstrates the epitaxial growth of 2H-TaS$_2$ few layers on GaN(0001), revealing structural, electronic, and interface properties crucial for integrating 2D materials with 3D semiconductors.

## Contribution

It reports the first epitaxial growth of 2H-TaS$_2$ on GaN(0001) and analyzes the interface and electronic interactions at high growth temperature.

## Key findings

- High-quality epitaxial growth at 825°C
- Unstrained 2D overlayer immediately after deposition
- Electron transfer from GaN to TaS$_2$ and nitrogen vacancies at interface

## Abstract

2H-TaS$_2$ few layers have been grown epitaxially onto GaN(0001). A high substrate growth temperature of 825$^{\circ}$C induces best structural properties of the overlayer, as revealed by in-situ electron diffraction (RHEED and LEED). The 2D-overlayer grows unstrained right after deposition of a monolayer. However, evidence of pits at the interface is provided by scanning transmission electron microscopy, most probably due to GaN thermal decomposition at the high growth temperature. In-situ x-ray photoemission spectroscopy shows core level shifts that are consistently related to electron transfer from the n-GaN(0001) to the 2H-TaS$_2$ epitaxial layer as well as the formation of a high concentration of nitrogen vacancies close to the interface. Further, no chemical reaction at the interface between the substrate and the grown TaS$_2$ overlayer is deduced from XPS, which corroborates the possibility of integration of 2D 2H-TaS$_2$ with an important 3D semiconducting material like GaN.