Comparison of the structure and optoelectronic properties of NO-adsorbed two-dimensional GaN with planar and hydrogenated structure

Abstract

This article investigates the difference between NO-absorbed planar and hydrogenated two-dimensional (2D) GaN under different adsorption conditions via first principles. The structure, stability, charge transfer, band structure, density of states and optical properties are analyzed in detail. Our results reveal that the NO shifts to Ga atom for planar 2D GaN and shifts to N atom for hydrogenated 2D GaN when NO is adsorbed perpendicular on two-dimensional GaN plane. Planar 2D GaN transmits electrons to NO while hydrogenated 2D GaN obtains electrons. Band structure and DOS show that there are two new impurity levels appear near CBM in spin-up band, which originated from hybridization of N p-orbitals and O p-orbitals in NO. The results indicate that NO-adsorbed 2D GaN possesses magnetic behaviors and magnetic moments of system are all from NO molecule. Stronger stability, lager charge transfer and bigger conductivity change make 2D GaN with planar structure be more sensitive for NO molecule, which can be used as NO gas sensors. Compared with planar 2D GaN, NO-adsorbed hydrogenated 2D GaN has better light absorption performance. In addition, changing adsorption method will significantly change characteristics of planar two-dimensional GaN.