Electronic fingerprint mechanism of NOx sensor based on single-material SnP3 logical junction

Abstract

Abstract An extraordinary sensing ability of the SnP3-based single-material logical junction for harmful NOx gases was explored in the present work through a set of first-principles electronic structure calculations. As a sensing platform, a metal-semiconductor-metal lateral junction composed of a single material was designed based on the metallic/semiconducting characteristics of trilayer/monolayer SnP3. Lacking a Schottky barrier at the electrode-channel interface, the gas-specific charge transfer between the SnP3 layer and gas molecules was precisely detected based on the current-voltage characteristics. NOx gases with strong adsorption strength and charge transfer amount on the SnP3 substrate were shown to be particularly well detected in this manner, in terms of either the absolute magnitude of the current or negative differential resistance (NDR) at a reasonably small bias voltage as a sensing signal. This work will provide a new pathway to design a Schottky barrier-free metal-semiconductor junction for highly sensitive sensor applications.