2D SiP Nanosheets as Efficient and Multi-Time Reversible Nanosensor for Nitrogen-Containing Gases

Abstract

Herein, we present the structural, electronic, and sensing properties of two-dimensional (2D) SiP nanosheets toward nitrogen-containing gases (NCG) like NH3, NO, and NO2 using density functional theory (DFT) calculations. All of the gas molecules are found to be physisorbed on the surface of the SiP nanosheet, as confirmed by the small values of adsorption energy. The exposure of NO and NO2 molecules induces a total magnetic moment of 1 μB on the nonmagnetic SiP nanosheet, thus making it suitable as a magnetic gas sensor. From the Bader charge analysis, it is observed that the NH3 molecule behaves as a donor, whereas NO and NO2 molecules behave as acceptors. Very short recovery times (τ) of 2.28 × 10–9, 7.78 × 10–5, and 1.71 × 10–3 s for NH3, NO, and NO2 gas molecules, respectively, on the SiP nanosheet are observed, thus indicating its fast, reversible, and multi-time reusable behavior. Further, for the real-world applications of NCGs@SiP, we investigated the current–voltage (I–V) characteristics and zero-bias transmission spectra using nonequilibrium Green’s function (NEGF) formalism. A substantial variation in the current is observed upon exposure of NH3, NO, and NO2 gas molecules on the SiP nanosheet. Therefore, we suggest a SiP nanosheet as an efficient, fast, and multi-time reusable nanosensor toward NCGs like NH3, NO, and NO2. Our study highlights the potential applications of the SiP nanosheet as a chemical and magnetic gas sensor for NCGs.