Enhanced Optoelectronic Response in Bilayer Lateral Heterostructures of Transition Metal Dichalcogenides

TL;DR

This paper demonstrates that bilayer lateral heterostructures of transition metal dichalcogenides exhibit significantly enhanced optoelectronic responses, including higher rectification currents, photovoltaic effects, and electroluminescence, compared to monolayer counterparts.

Contribution

It reports the controlled synthesis of multi-junction bilayer heterostructures with superior optoelectronic properties, expanding the potential of 2D materials in flexible electronics.

Findings

Nearly tenfold higher rectification currents in bilayer heterostructures

Photovoltaic response with short circuit currents ~1000 times larger than monolayers

Room-temperature electroluminescence observed in bilayer heterostructures

Abstract

Two-dimensional lateral heterojunctions are basic components for low-power and flexible optoelectronics. In contrast to monolayers, devices based on few-layer lateral heterostructures could offer superior performance due to their lower susceptibility to environmental conditions. Here, we report the controlled synthesis of multi-junction bilayer lateral heterostructures based on MoS2-WS2 and MoSe2-WSe2, where the hetero-junctions are created via sequential lateral edge-epitaxy that happens simultaneously in both the first and the second layer. With respect to their monolayer counterparts, bilayer lateral heterostructures yield nearly one order of magnitude higher rectification currents. They also display a clear photovoltaic response, with short circuit currents ~103 times larger than those extracted from the monolayers, in addition to room-temperature electroluminescence. The superior performance of bilayer heterostructures significantly expands the functionalities of 2D crystals.