Two-Dimensional Tetragonal GaN as Potential Molecule Sensors for NO and NO₂ Detection: A First-Principle Study

Properties of gas molecules (NO, NH₃, and NO₂) adsorbed on two-dimensional GaN with a tetragonal structure (T-GaN) are studied using first-principles methods. Adsorption energy, adsorption distance, Hirshfeld charge, electronic properties, electric conductivity, and recovery time are calculated. It is found that these three molecules are all chemisorbed on the T-GaN with reasonable adsorption energies and apparent charge transfer. The electronic properties of the T-GaN present dramatic changes after the adsorption of NO₂ and NO molecules, especially its electric conductivity, but NH₃ molecule hardly changes the electronic properties of the T-GaN. Furthermore, the recovery time of the T-GaN sensor at T = 300 K is estimated to be quite short for NO₂ and NO but very long for NH₃. Moreover, the magnetic properties of the T-GaN are changed obviously due to the adsorption of NO (or NO₂) molecule. Therefore, we suggest that the T-GaN can be a prominent candidate for application as NO₂ and NO molecule sensors.