中国物理B ›› 2012, Vol. 21 ›› Issue (6): 67103-067103.doi: 10.1088/1674-1056/21/6/067103

• CONDENSED MATTER: ELECTRONIC STRUCTURE, ELECTRICAL, MAGNETIC, AND OPTICAL PROPERTIES • 上一篇    下一篇

Comparative study of adsorption characteristics of Cs on the GaN (0001) and GaN (0001) surfaces

杜玉杰a b, 常本康a, 王洪刚a, 张俊举a, 王美山c   

  1. a. Department of Physics and Electronic Sciences, Institute of Bingzhou, Bingzhou 256603, China;
    b. Institute of Electronic Engineering and Opto-Electric Technology, Nanjing University ofScience and Technology, Nanjing 210094, China;
    c. School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China
  • 收稿日期:2012-01-28 修回日期:2012-02-28 出版日期:2012-05-01 发布日期:2012-05-01
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 60871012 and 61171042), the Natural Science Foundation of Shandong Province of China (Grant No. ZR2010FL018), and the Higher Educational Science and Technology Program of Shandong Province, China (Grant No. J10LG74).

Comparative study of adsorption characteristics of Cs on the GaN (0001) and GaN (0001) surfaces

Du Yu-Jie(杜玉杰)a)b), Chang Ben-Kang(常本康)a)†, Wang Hong-Gang(王洪刚)a), Zhang Jun-Ju(张俊举)a), and Wang Mei-Shan(王美山) c)   

  1. a. Department of Physics and Electronic Sciences, Institute of Bingzhou, Bingzhou 256603, China;
    b. Institute of Electronic Engineering and Opto-Electric Technology, Nanjing University ofScience and Technology, Nanjing 210094, China;
    c. School of Physics and Optoelectronic Engineering, Ludong University, Yantai 264025, China
  • Received:2012-01-28 Revised:2012-02-28 Online:2012-05-01 Published:2012-05-01
  • Contact: Chang Ben-Kang E-mail:bkchang@mail.njust.edu.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 60871012 and 61171042), the Natural Science Foundation of Shandong Province of China (Grant No. ZR2010FL018), and the Higher Educational Science and Technology Program of Shandong Province, China (Grant No. J10LG74).

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摘要： The adsorption characteristics of Cs on GaN (0001) and GaN (0001) surfaces with a coverage from 1/4 to 1 monolayer have been investigated using the density functional theory with a plane-wave ultrasoft pseudopotential method based on first-principles calculations. The results show that the most stable position of the Cs adatom on the GaN (0001) surface is at the N-bridge site for 1/4 monolayer coverage. As the coverage of Cs atoms at the N-bridge site is increased, the adsorption energy reduces. As the Cs atoms achieve saturation, the adsorption is no longer stable when the coverage is 3/4 monolayer. The work function achieves its minimum value when the Cs adatom coverage is 2/4 monolayer, and then rises with Cs atomic coverage. The most stable position of Cs adatoms on the GaN (0001) surface is at H3 site for 1/4 monolayer coverage. As the Cs atomic coverage at H3 site is increased, the adsorption energy reduces, and the adsorption is still stable when the Cs adatom coverage is 1 monolayer. The work function reduces persistently, and does not rise with the increase of Cs coverage.

关键词: GaN surface, electronic structure, adsorption energy, work function

Abstract: The adsorption characteristics of Cs on GaN (0001) and GaN (0001) surfaces with a coverage from 1/4 to 1 monolayer have been investigated using the density functional theory with a plane-wave ultrasoft pseudopotential method based on first-principles calculations. The results show that the most stable position of the Cs adatom on the GaN (0001) surface is at the N-bridge site for 1/4 monolayer coverage. As the coverage of Cs atoms at the N-bridge site is increased, the adsorption energy reduces. As the Cs atoms achieve saturation, the adsorption is no longer stable when the coverage is 3/4 monolayer. The work function achieves its minimum value when the Cs adatom coverage is 2/4 monolayer, and then rises with Cs atomic coverage. The most stable position of Cs adatoms on the GaN (0001) surface is at H3 site for 1/4 monolayer coverage. As the Cs atomic coverage at H3 site is increased, the adsorption energy reduces, and the adsorption is still stable when the Cs adatom coverage is 1 monolayer. The work function reduces persistently, and does not rise with the increase of Cs coverage.

Key words: GaN surface, electronic structure, adsorption energy, work function

中图分类号:  (III-V semiconductors)

  • 71.55.Eq
78.20.Ci (Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity))