First-Principles Calculations of SiBi Nanosheets as Sensors for Oxygen-Containing Gases

First-principles calculations are performed to investigate the approachable application of a two-dimensional SiBi nanosheet as an oxygen-containing gas (OCG) sensor material. Through detailed analysis of modifications in the electronic parameters, adsorption energies, work function, and charge transfer between the surface and gas molecules, the physisorption nature of CO2, SO2, and NO2 on the surface of SiBi nanosheets is observed via van der Waals force, while the chemisorption nature is noticed for O2. The maximum charge transfer (0.59 e) is found for NO2 gas, which strongly suggests a more sensible interaction of the NO2 molecule with the SiBi nanosheet, while quite a low charge transfer (-0.06 e) for the CO2 molecule is observed. Due to the charge transfer from the molecules to the surface, all the molecules except for CO2 preserve the electron donor nature. The charge transfers of these gas molecules adsorbed on the SiBi nanosheet are observed to be much larger compared to the same for other reported 2D materials, such as graphene, germanene, blue phosphorene, etc. The recovery time (τ) at room temperature (300 K) is observed to be very short for SO2 (1.67 ns) and CO2 (0.73 ps), which strongly suggests that the SiBi monolayer is a better ultra-fast reversible and multi-time reusable/recyclable molecular sensor for OCGs. The efficiency of the SiBi nanosheet in terms of significant current-voltage (I-V) response for superior OCG sensing is confirmed by the anisotropic transport characteristics using the nonequilibrium Green's function (NEGF) approach. Therefore, the present investigation certainly provides insights into possible ways of further fundamental exploration of OCG molecule sensors based on 2D materials and its real-world applications.