Electronic Fingerprint Mechanism of NOx Sensor Based on Single-Material SnP3 Logical Junction

An extraordinary sensing ability of the SnP 3 -based single-material logical junction for harmful NO x 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 SnP 3 . Lacking a Schottky barrier at the electrode-channel interface, the gas-specific charge transfer between the SnP 3 layer and gas molecules was precisely detected based on the current-voltage characteristics. NO x gases with strong adsorption strength and charge transfer amount on the SnP 3 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.