A two-step chemical vapor deposition process for the growth of continuous vertical heterostructure WSe2/h-BN and its optical properties

Abstract

The expansion of two-dimensional (2D) van der Waals heterostructure materials growth and synthesis leads to impressive results in the development and improvement of electronic and optoelectronic applications. Herein, a vertical WSe₂/hBN heterostructure was obtained via a dual CVD system, in which prior to the WSe₂ growth a continuous monolayer hBN was obtained on a SiO₂/Si substrate. Comparing growth on SiO₂/Si and quartz substrates, we found that the underlayer of hBN leads to a desorption/diffusion process of tungsten (W) and selenium (Se) producing high-quality and large-area WSe₂ growth. In contrast with WSe₂/SiO₂ and WSe₂/quartz heterostructures, the photoluminescence properties of WSe₂/hBN exhibit a sharp intense WSe₂ peak at 790 nm with a narrow full width at half-maximum (80 meV) due to no dangling bonds and dielectric effect of the hBN interface. The photoluminescence results suggest that the WSe₂/hBN heterostructure has high crystallinity with a defect-free interface.