中国物理B ›› 2012, Vol. 21 ›› Issue (6): 67306-067306.doi: 10.1088/1674-1056/21/6/067306

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

Modulation of electrical and optical properties of gallium-doped ZnO films by radio frequency magnetron sputtering

梁爽, 梅增霞, 杜小龙   

  1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
  • 收稿日期:2011-12-21 修回日期:2012-02-10 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. 61076007 and 11174348), the National Basic Research Program of China (Grant Nos. 2009CB929404 and 2011CB302002), and the Knowledge Innovation Project of the Chinese Academy of Sciences.

Modulation of electrical and optical properties of gallium-doped ZnO films by radio frequency magnetron sputtering

Liang Shuang(梁爽), Mei Zeng-Xia(梅增霞)†, and Du Xiao-Long(杜小龙)   

  1. Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
  • Received:2011-12-21 Revised:2012-02-10 Online:2012-05-01 Published:2012-05-01
  • Contact: Mei Zeng-Xia E-mail:zxmei@aphy.iphy.ac.cn
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 61076007 and 11174348), the National Basic Research Program of China (Grant Nos. 2009CB929404 and 2011CB302002), and the Knowledge Innovation Project of the Chinese Academy of Sciences.

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摘要： Ga-doped ZnO (GZO) films are prepared on amorphous glass substrates at room temperature by radio frequency magnetron sputtering. The results reveal that the gallium doping efficiency, which will have an important influence on the electrical and optical properties of the film, can be governed greatly by the deposition pressure and film thickness. The position shifts of the ZnO (002) peaks in X-ray diffraction (XRD) measurements and the varied Hall mobility and carrier concentration confirms this result. The low Hall mobility is attributed to the grain boundary barrier scattering. The estimated height of barrier decreases with the increase of carrier concentration, and the trapping state density is nearly constant. According to defect formation energies and relevant chemical reactions, the photoluminescence (PL) peaks at 2.46 eV and 3.07 eV are attributed to oxygen vacancies and zinc vacancies, respectively. The substitution of more Ga atoms for Zn vacancies with the increase in film thickness is also confirmed by the PL spectrum. The obvious blueshift of the optical bandgap with an increase of carrier concentration is explained well by the Burstein-Moss (BM) effect. The bandgap difference between 3.18 eV and 3.37 eV, about 0.2 eV, is attributed to the metal-semiconductor transition.

关键词: doping efficiency, Hall mobility, photoluminescence, Burstein-Moss effect

Abstract: Ga-doped ZnO (GZO) films are prepared on amorphous glass substrates at room temperature by radio frequency magnetron sputtering. The results reveal that the gallium doping efficiency, which will have an important influence on the electrical and optical properties of the film, can be governed greatly by the deposition pressure and film thickness. The position shifts of the ZnO (002) peaks in X-ray diffraction (XRD) measurements and the varied Hall mobility and carrier concentration confirms this result. The low Hall mobility is attributed to the grain boundary barrier scattering. The estimated height of barrier decreases with the increase of carrier concentration, and the trapping state density is nearly constant. According to defect formation energies and relevant chemical reactions, the photoluminescence (PL) peaks at 2.46 eV and 3.07 eV are attributed to oxygen vacancies and zinc vacancies, respectively. The substitution of more Ga atoms for Zn vacancies with the increase in film thickness is also confirmed by the PL spectrum. The obvious blueshift of the optical bandgap with an increase of carrier concentration is explained well by the Burstein-Moss (BM) effect. The bandgap difference between 3.18 eV and 3.37 eV, about 0.2 eV, is attributed to the metal-semiconductor transition.

Key words: doping efficiency, Hall mobility, photoluminescence, Burstein-Moss effect

中图分类号:  (II-VI semiconductors)

  • 73.61.Ga
78.55.Et (II-VI semiconductors) 72.10.Fk (Scattering by point defects, dislocations, surfaces, and other imperfections (including Kondo effect)) 81.15.Cd (Deposition by sputtering)