Two-Dimensional Tetragonal GaN as Potential Molecule Sensors for NO and NO(2) Detection: A First-Principle Study.

Properties of gas molecules (NO, NH(3), and NO(2)) 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 NO(2) and NO molecules, especially its electric conductivity, but NH(3) 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 NO(2) and NO but very long for NH(3). Moreover, the magnetic properties of the T-GaN are changed obviously due to the adsorption of NO (or NO(2)) molecule. Therefore, we suggest that the T-GaN can be a prominent candidate for application as NO(2) and NO molecule sensors.