title: Influence of vacancy defect on surface feature and adsorption of Cs on GaN(0001) surface.
abstract: The effects of Ga and N vacancy defect on the change in surface feature, work function, and characteristic of Cs adsorption on a (2 × 2) GaN(0001) surface have been investigated using density functional theory with a plane-wave ultrasoft pseudopotential method based on first-principles calculations. The covalent bonds gain strength for Ga vacancy defect, whereas they grow weak for N vacancy defect. The lower work function is achieved for Ga and N vacancy defect surfaces than intact surface. The most stable position of Cs adatom on Ga vacancy defect surface is at T1 site, whereas it is at B(Ga) site on N vacancy defect surface. The E(ads) of Cs on GaN(0001) vacancy defect surface increases compared with that of intact surface; this illustrates that the adsorption of Cs on intact surface is more stable.
authors.affiliation: Department of Optoelectronic Engineering, Binzhou University, Binzhou 256603, China.
authors.forename: Yanjun
authors.initials: Y
authors.lastname: Ji
authors.affiliation: Department of Optoelectronic Engineering, Binzhou University, Binzhou 256603, China ; Institute of Electronic Engineering and Opto-Electric Technology, Nanjing University of Science and Technology, Nanjing 210094, China.
authors.forename: Yujie
authors.initials: Y
authors.lastname: Du
authors.affiliation: School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China.
authors.forename: Meishan
authors.initials: M
authors.lastname: Wang
mesh_terms: D000327:Adsorption; D002586:Cesium / Q000737:chemistry*; D005708:Gallium / Q000737:chemistry*; D008956:Models, Chemical; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D002586:Cesium; C473348:gallium nitride; D005708:Gallium