Bilayer CdS Structure: A Promising Candidate for Photocatalytic and Optoelectronic Applications

Abstract

Density functional theory methodology has been adopted to investigate the structural, electronic, and optical properties of the CdS bilayer system and compare it with the CdS monolayer. For the bilayer system, five different types of stacking modes have been considered. The binding energy calculation suggests that the AA2 stacking mode is the most energetically favorable. Both the CdS monolayer and AA2 stacked CdS bilayer possess hexagonal symmetry, but the lattice constant slightly increases in the case of the AA2 stacked CdS bilayer compared to the monolayer. The negative formation energy also concludes that the formation of both systems is thermodynamically favorable. Ab initio molecular dynamics simulation further confirms the thermodynamic stability of the AA2 stacked CdS bilayer system. The band gap increases in the bilayer system compared to the monolayer as well as the bulk form, and both systems show direct band gap semiconducting character. Similar to the monolayer, the CdS bilayer system is also a promising candidate for visible light-driven photocatalysis. The optical band gap calculation for CdS sheets shows its possible usage as a light harvester. Moreover, the optical band gap, as well as absorption spectra, shows a redshift for the AA2 stacked CdS bilayer as compared to the CdS monolayer. A redshift in the optical band gap, as well as the absorption spectra, is observed for the AA2 stacked CdS bilayer with respect to the monolayer. The CdS monolayer and bilayer systems exhibit outstanding optical responses that confirm their potential applications in optoelectronics.

Density Functional Theory Studies of van der Waals Heterostructures Comprised of MoSi2P4 and BAs Monolayers for Solar Cell Applications

“…The physical phenomena and potential applications of two-dimensional (2D) stacking materials have initiated significant interest in the fields of nanoelectronics, visible-light-driven photocatalysts, energy storage, and conversion. − However, studies have shown that homostructure-layered materials may limit device applications. To overcome this limitation, integration of the inherent characteristics of two or more 2D monolayers has been widely regarded as the most promising method through the construction of van der Waals heterostructures (vdW-HSs). , Stacked layers of 2D materials in vdW-HSs are blended by weak van der Waals forces. This has recently emerged as a promising platform for the development of ultrafast and low-power electronic and spintronic devices.…”

“…To overcome this limitation, integration of the inherent characteristics of two or more 2D monolayers has been widely regarded as the most promising method through the construction of van der Waals heterostructures (vdW-HSs). 4,5 Stacked layers of 2D materials in vdW-HSs are blended by weak van der Waals forces. This has recently emerged as a promising platform for the development of ultrafast and low-power electronic and spintronic devices.…”

Investigation of the electronic and optical properties of bilayer CdS as a gas sensor: first-principles calculations

“…This unique property allows CdS gas sensors to operate effectively at room temperature, eliminating the need for external heating. 67,68 Consequently, there is a need to explore CdS as a novel material in the gas sensor eld. Therefore, 2D CdS bilayers emerge as excellent candidates for highly sensitive gas sensors, given their potential for exceptional gas-sensing capabilities.…”