Characteristics of lateral and hybrid heterostructures based on monolayer MoS2: a computational study

Abstract

Novel MoS₂/(MX₂)_n lateral and (MoS₂)/(MX₂)_n–BN hybrid heterostructures have been designed on monolayer MoS₂ to extend its applications. The electronic, interfacial and optical properties of the lateral and hybrid heterostructures have been investigated comparatively using first-principles calculations. It was found that the charge distributions, band gaps, band levels, electrostatic potentials, and optical absorption of the MoS₂/(MX₂)_n lateral heterostructures depend greatly on the width n of MX₂, irrespective of the size of the lateral heterostructures. The CBM states of the MoS₂/(MX₂)_n lateral heterostructures dominated by the d_z² orbitals are localized around MoS₂, whereas the VBM states of the MoS₂/(MX₂)_n lateral heterostructures are dominated by the MX₂ region. Through regulating the width n of the MX₂ region in the MoS₂/(MX₂)_n lateral heterostructures, the optical absorption of the lateral heterostructures under visible light can be increased, and the CBM and VBM states of the lateral heterostructures can be located above the hydrogen reduction potential and below the water oxidation potential, respectively. The similar characteristics were observed in the MoS₂/(MX₂)_n–BN hybrid heterostructures, indicating that BN is a good substrate for the MoS₂/(MX₂)_n lateral heterostructures. The analysis implies that forming the lateral and hybrid heterostructures is an effective way to extend the applications of monolayer MoS₂ in photocatalytic water and photovoltaic devices.