The structural, electronic and optical properties of novel GaP/ZnS/AlP multilayer heterostructure: first-principles study

Abstract

Theoretical prediction and development of layered semiconductor heterostructure has always been one of the hotspots in the field of materials. By coupling the monolayer structure of the (1 1 1) of GaP, ZnS and AlP unit cells, we construct a kind of multilayer heterostructure. And using the first-principles calculation with density functional theory, the stacking orders, electronic and optical properties of the heterostructure were systematically investigated. The results show that for the C3-stacking which makes ZnS as the intermediate layer, the binding energy is −9.42 eV, and it have the most stable structure and an indirect band gap of 0.760 eV. In this system, the electrons will accumulate between the bonding atoms of monolayers and consume around the atoms, moreover, some of the electrons will transfer between monolayers. The optical absorption of multilayer heterostructure has been greatly improved compared with isolated monolayers, especially in the ultraviolet region. In addition, its wavelength distribution of high optical absorption extends to the visible light region, which provides a basis for enhancing photocatalytic activity under solar illumination. During the changes of the interlayer spacing and the external electric field, the band gap of the heterostructure exhibits tunable and there are direct-indirect and semiconductor-metal transition points, which will further affect optical properties. The stabilized atomically thin layered materials, excellent optical property and tunable band gap of the multilayer heterostructure mean that its great potential in the optoelectronic devices and photocatalytic applications.