# WS2 with Controllable Layer Number Grown Directly on W Film

## TL;DR

This paper introduces a new method to grow high-quality WS2 layers directly on tungsten films by controlling temperature and precursor thickness.

## Contribution

The study proposes an innovative method to directly grow WS2 with controllable layer numbers on tungsten films.

## Key findings

- Reaction temperature regulates WS2 growth direction: horizontal below 950 °C and vertical above 1000 °C.
- Precursor film thickness controls the number of WS2 layers, confirmed by Raman and band gap measurements.

## Abstract

As a layered material with single/multi-atom thickness, two-dimensional transition metal sulfide WS2 has attracted extensive attention in the field of science for its excellent physical, chemical, optical, and electrical properties. The photoelectric properties of WS2 are even more promising than graphene. However, there are many existing preparation methods for WS2, but few reports on its direct growth on tungsten films. Therefore, this paper studies its preparation method and proposes an innovative two-dimensional material preparation method to grow large-sized WS2 with higher quality on metal film. In this experiment, it was found that the reaction temperature could regulate the growth direction of WS2. When the temperature was below 950 °C, the film showed horizontal growth, while when the temperature was above 1000 °C, the film showed vertical growth. At the same time, through Raman and band gap measurements, it is found that the different thicknesses of precursor film will lead to a difference in the number of layers of WS2. The number of layers of WS2 can be controlled by adjusting the thickness of the precursor.