Novel\nRed Emission from MoO₃/MoS₂–MoO₂–MoO₃ Core–Shell\nBelt Surface

Abstract

Electrically\ndriven red emission from MoS₂–MoO₂–MoO₃ (MS-MO) hybrid-based metal–semiconductor–metal\n(MSM) devices is reported for the first time. MoO₃ belts\nwith high crystal quality and sufficient size are synthesized by thermal\ndeposition. A layer of MS-MO hybrid is then produced on the belt surface\nto form MoO₃/MS-MO core–shell by sulfurization.\nThe devices exhibit unique electrical properties, a nonlinear <i>I</i>–<i>V</i> curve, and electric hysteresis\ncharacteristics at high applied biases (>2.4 V), where MS-MO hybrids\nact as electron transport channels. The electroluminescent current\nof the device increases to a set current limit over time when a constant\nbias is applied. The novel characteristics of the device are attributed\nto the space charge limited conduction (SCLC) mechanism occurring\nin MS-MO hybrids. The strong light emission is from recombination\nof excitons within the MoS₂ phase. This work develops a\nsimple and effective method to drive MoS₂ to emit light\non a large scale without using monolayer MoS₂ and vertical\np–n junctions, indicating great potential for future 2D optoelectronics\nand photonics applications.