Interfacial engineering based on an Al2CO and SiC heterostructure to explore the gas sensing mechanism using first-principles strategies

Abstract

Two-dimensional (2D) materials and their van der Waals (vdW) heterostructures have been considered promising for application as gas detecting devices owing to their distinct physical and chemical characteristics. In this work, we theoretically investigated Al₂CO/SiC heterostructure using semiconductor SiC as a substrate by density functional theory (DFT) calculations to explore its potential for outstanding performance. Our research focused on the comparative analysis of the adsorption properties of six gas molecules (H₂, NH₃, SO₂, NO, O_2, and H₂O) with SiC and its heterostructure. The structural properties, electronic properties, charge transfer mechanism, dynamic and thermal stabilities of the heterostructure were investigated by geometry optimization, single-point calculation, Hirshfeld charge analysis, phonon spectra and ab initio molecular dynamics calculations, respectively. The adsorption configurations for all adsorbed gases and work functions (WFs) were calculated to explore the sensing performance of the Al₂CO/SiC heterostructure. Our findings indicated semiconductor behavior after the formation of the Al₂CO/SiC heterostructure. Interestingly, the Al₂CO/SiC heterostructure was investigated for its adsorption of gas molecules (H₂, NH₃, SO₂, NO, O_2, and H₂O) and was found to be sensitive to the chemisorption of NH₃, SO₂, NO, O_2, and H₂O with average adsorption energy (E_ads) and a significant amount of charge transfer. The Al₂CO/SiC gas sensor demonstrated a recovery time of 1.84 × 10² and 0.27 s for detecting NO and NH₃ respectively. Furthermore, compared to the SiC monolayer the heterostructure Al₂CO/SiC illustrates excellent potential for application as a gas sensor to detect NO and NH₃ gases.