Chemical sensing by band modulation of a black phosphorus/molybdenum diselenide van der Waals hetero-structure

Abstract

We report on a new chemical sensor based on black phosphorus/molybdenum diselenide van der Waals hetero-junctions. Due to the atomically thin nature of two-dimensional (2D) materials, surface adsorption of gas molecules can effectively modulate the band alignment at the junction interface, making the device a highly sensitive detector for chemical adsorptions. Compared to sensors made of homogeneous nanomaterials, the hetero-junction demonstrates considerably lower detection limit and higher sensitivity toward nitrogen dioxide. Kelvin probe force microscopy and finite element simulations have provided experimental and theoretical explanations for the enhanced performance, proving that chemical adsorption can induce significant changes in band alignment and carrier transport behaviors. The study demonstrates the potential of van der Waals hetero-junction as a new platform for sensing applications, and provides more insights into the interaction between gaseous molecules and 2D hetero-structures.

Recent Progress in Black‐Phosphorus‐Based Heterostructures for Device Applications

“…Scale bar is 1 µm. Reproduced with permission . Copyright 2016, IOP Publishing Ltd. f) Schematic of device based on BP‐ZnO heterojunction.…”

“…Previous report has shown that FETs based on multilayer BP can work as a chemical sensor of nitrogen dioxide (NO 2 ) due to the immediate increase in conductivity of the device upon exposure of NO 2 . Recently, a chemical sensor made of the vdWs heterostructure of BP and MoSe 2 has shown extremely low detection limit and much higher chemical sensitivity to NO 2 compared with the BP–MoSe 2 ‐based sensors constructed on the same chip . The surface potential of the device was characterized by the Kelvin probe force microscopy (KPFM), exhibiting almost identical images for the region before and after exposure to NO 2 , which testifies good recovery property of the chemical sensor (Figure e).…”

MoS2 Van der Waals p–n Junctions Enabling Highly Selective Room‐Temperature NO2 Sensor

“…Heterostructures, especially p–n junctions of 2D materials, are recently attracting increasing attention for their implementation in nanodevices. [ 23–28 ] Van der Waals heterostructures formed by stacking of various 2D materials display physical properties that are between those of the two materials and display a carrier concentration gradient at their interface. Owing to the atomic thickness, the carrier concentration and energy band diagram of the heterostructure can be effectively modulated by various means, e.g., electrical, magnetic, and optical, enabling new possibilities for high‐performance gas sensors.…”

“…Owing to the atomic thickness, the carrier concentration and energy band diagram of the heterostructure can be effectively modulated by various means, e.g., electrical, magnetic, and optical, enabling new possibilities for high‐performance gas sensors. Despite a number of studies have reported sensor applications of 2D heterojunctions based on different materials, [ 23–28 ] the performances of p–n homojunctions have not yet been investigated.…”

The Art of Constructing Black Phosphorus Nanosheet Based Heterostructures: From 2D to 3D

“…Reproduced with permission. [ 155 ] Copyright 2016, IOP Publishing. c) Schematic illustration of BP before sodiation, with the first step of sodium‐ion intercalation, and the second step of alloy reaction in sodium‐ion batteries.…”