中国物理B ›› 2009, Vol. 18 ›› Issue (9): 4013-4018.doi: 10.1088/1674-1056/18/9/066

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Optical properties of hexagonal boron nitride thin films deposited by radio frequency bias magnetron sputtering

邓金祥1, 汪旭洋1, 陈光华1, 张晓康2, 姚倩3, 贺德衍3   

  1. (1)School of Applied Mathematics and Physics, Beijing University of Technology, Beijing 100124, China; (2)School of Applied Mathematics and Physics, Beijing University of Technology, Beijing 100124, China;School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China; (3)School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China
  • 收稿日期:2008-11-15 修回日期:2009-04-13 出版日期:2009-09-20 发布日期:2009-09-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grants Nos 60876006 and 60376007) and the Natural Science Foundation of Beijing (Grants No 4072007).

Optical properties of hexagonal boron nitride thin films deposited by radio frequency bias magnetron sputtering

Deng Jin-Xiang(邓金祥)a)†, Zhang Xiao-Kang(张晓康)a)b), Yao Qian(姚倩)b), Wang Xu-Yang(汪旭洋)a), Chen Guang-Hua(陈光华)a), and He De-Yan(贺德衍)b)   

  1. a School of Applied Mathematics and Physics, Beijing University of Technology, Beijing 100124, China; b School of Physical Science and Technology, Lanzhou University, Lanzhou 730000, China
  • Received:2008-11-15 Revised:2009-04-13 Online:2009-09-20 Published:2009-09-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grants Nos 60876006 and 60376007) and the Natural Science Foundation of Beijing (Grants No 4072007).

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摘要： The optical properties of hexagonal boron nitride (h-BN) thin films were studied in this paper. The films were characterized by Fourier transform infrared spectroscopy, UV--visible transmittance and reflection spectra. h-BN thin films with a wide optical band gap Eg (5.86 eV for the as-deposited film and 5.97 eV for the annealed film) approaching h-BN single crystal were successfully prepared by radio frequency (RF) bias magnetron sputtering and post-deposition annealing at 970~K. The optical absorption behaviour of h-BN films accords with the typical optical absorption characteristics of amorphous materials when fitting is made by the Urbach tail model. The annealed film shows satisfactory structure stability. However, high temperature still has a significant effect on the optical absorption properties, refractive index n, and optical conductivity σ of h-BN thin films. The blue-shift of the optical absorption edge and the increase of Eg probably result from stress relaxation in the film under high temperatures. In addition, it is found that the refractive index clearly exhibits different trends in the visible and ultraviolet regions. Previous calculational results of optical conductivity of h-BN films are confirmed in our experimental results.

Abstract: The optical properties of hexagonal boron nitride (h-BN) thin films were studied in this paper. The films were characterized by Fourier transform infrared spectroscopy, UV--visible transmittance and reflection spectra. h-BN thin films with a wide optical band gap Eg (5.86 eV for the as-deposited film and 5.97 eV for the annealed film) approaching h-BN single crystal were successfully prepared by radio frequency (RF) bias magnetron sputtering and post-deposition annealing at 970 K. The optical absorption behaviour of h-BN films accords with the typical optical absorption characteristics of amorphous materials when fitting is made by the Urbach tail model. The annealed film shows satisfactory structure stability. However, high temperature still has a significant effect on the optical absorption properties, refractive index n, and optical conductivity $\sigma$ of h-BN thin films. The blue-shift of the optical absorption edge and the increase of Eg probably result from stress relaxation in the film under high temperatures. In addition, it is found that the refractive index clearly exhibits different trends in the visible and ultraviolet regions. Previous calculational results of optical conductivity of h-BN films are confirmed in our experimental results.

Key words: hexagonal boron nitride films, sputtering, UV--visible, optical properties

中图分类号:  (III-V semiconductors)

  • 78.66.Fd
68.55.-a (Thin film structure and morphology) 78.20.Ci (Optical constants (including refractive index, complex dielectric constant, absorption, reflection and transmission coefficients, emissivity)) 78.30.Fs (III-V and II-VI semiconductors) 78.40.Fy (Semiconductors) 81.15.Cd (Deposition by sputtering)