Monolayer MoSe2/NiO van der Waals heterostructures for infrared light-emitting diodes

Abstract

Nowadays monolayer transition metal chalcogenides (TMCs) have been widely researched due to their excellent optoelectronic properties. However, the preparation of large-sized monolayer TMCs and high-power TMC-based light-emitting diodes are still full of challenges, which limit their application in two-dimensional devices. Here, the large-sized monolayer single-crystalline MoSe₂ was synthesized by chemical vapor deposition. The influence of the relative gas pressure ratio of MoO₃ to Se on MoSe₂ morphology is discussed. The TEM analysis confirmed the presence of 2H-phase monolayer MoSe₂. A photoluminescence peak from the MoSe₂ monolayer is detected at about 804 nm, illustrating an intrinsic energy bandgap of 1.54 eV. Importantly, a novel 2D/3D heterostructure, monolayer MoSe₂/NiO van der Waals heterostructure, is constructed for a light-emitting diode (LED). The electroluminescence peaks of n-MoSe₂/p-NiO LED locate at 812 nm, 848 nm and 918 nm, all of which are in the infrared light range. Interestingly, the electroluminescence peaks of our n-MoSe₂/p-NiO LED are close to those of conventional air conditioner telecontrollers. So the n-MoSe₂/p-NiO infrared LED is forward to be used in infrared remote sensing systems in the future.