Vertical CVD Growth of Highly Uniform Transition Metal Dichalcogenides

TL;DR

This paper introduces a vertical chemical vapor deposition method that enables the growth of highly uniform, wafer-scale monolayer transition metal dichalcogenides with excellent reproducibility, addressing key challenges in 2D material fabrication.

Contribution

The authors develop a VCVD technique that precisely controls growth parameters, resulting in uniform, high-quality 2D TMDCs over large areas, surpassing traditional horizontal CVD limitations.

Findings

VCVD-grown TMDCs show high uniformity and quality over centimeter-scale substrates.

The method allows for reproducible growth of monolayer TMDCs like MoS2 and WS2.

Successful fabrication of van der Waals heterostructures from VCVD-grown TMDCs.

Abstract

Two-dimensional (2D) transition metal dichalcogenides (TMDCs) have attracted great attention due to their physical and chemical properties that make them promising in electronics and optoelectronics. Because of the difficulties in controlling concentrations of solid precursors and spatially non-uniform growth dynamics, it is challenging to grow wafer-scale 2D TMDCs with good uniformity and reproducibility so far, which significantly hinders their practical use. Here we report a vertical chemical vapor deposition (VCVD) design to grow monolayer TMDCs with a uniform density and high quality over the whole wafer, and with excellent reproducibility. The use of such VCVD design can easily control the three key growth parameters of precursor concentration, gas flow and temperature, which cannot be done in currently widely-used horizontal CVD system. Statistical results show that VCVD-grown monolayer TMDCs including MoS2 and WS2 are of high uniformity and quality on substrates over centimeter size. We also fabricated multiple van der Waals heterostructures by the one-step transfer of VCVD-grown TMDC samples, owning to its good uniformity. This work opens a way to grow 2D materials with high uniformity and reproducibility on the wafer scale, which can be used for the scalable fabrication of 2D materials and their heterostructures.