Study on electronic properties and charge transfer doping of organic molecules adsorbed g-GaN monolayer

Two-dimensional GaN has attracted much attention owing to its excellent electronic and photoelectric properties. Tuning charge transfer and electronic characteristics of g-GaN are essential to its applications in electronic and optoelectronic devices. In this work, the electronic structures and charge transfer of organic molecules adsorbed g-GaN systems tetracyanoethylene (TCNE)/g-GaN, tetracyanoquinodimethane (TCNQ)/g-GaN, and tetrathiafulvalene (TTF)/g-GaN are explored based on first-principles. The results show that the TCNE and TCNQ molecules inject additional holes into g-GaN monolayer, and p-type doping is achieved in g-GaN monolayer. While a deep impurity level is introduced to TTF/g-GaN doping system, and the TTF injects minute quantities of additional electrons into g-GaN monolayer. The charge transfer and electronic characteristics of TCNE/g-GaN, TCNQ/g-GaN, and TTF/g-GaN doping systems are sensitive to applied vertical electric field. Our work has great potential for g-GaN application in nano electronic and photoelectric devices.