In Situ Physicochemical Assessment of Gallium Nitride Nanosheet Sensor Towards Gas Detecting: A DFT Study

This article aims to study the adsorption of hazardous gases of nitric oxide (NO), nitrogen dioxide (NO2) and ammonia (NH3) by using monolayer graphitic GaN nanosheet with the employing density functional theory (DFT). The changes of charge density have shown a more important charge transfer for hexagonal honeycomb nanosheet of gallium nitride (GaN) which acts as the electron acceptor while gas molecules act as the stronger electron donors through adsorption on the graphitic-like GaN surface. The adsorption of NO and NO2 molecules introduced spin polarization in the GaN sheet, indicating that it can be employed as a magnetic gas sensor for NO and NO2 sensing. The partial density of states (PDOS) graphs have explained that the NO and NO2 states in GaN nanosheet, respectively, have more of the conduction band between –5 to –10 eV, while nitrogen and oxygen states have minor contributions. Ga sites in GaN nanosheet have higher interaction energy from Van der Waals' forces with gas molecules. GaN nanosheet represents having enough capability for adsorbing gases of NO, NO2 and NH3 through charge transfer from nitrogen atom and oxygen atom to the gallium element owing to intra-atomic and interatomic interactions.