Preparation and optical band gap of Al doped Mg2Si thin films

Abstract

Abstract: The Al-doped Mg2Si thin films on Si substrates are fabricated by magnetron sputtering method. Influences of doping levels on the compositions, surface topographies, roughness and optical band gap values of Mg2Si thin films are investigated with X-ray diffraction (XRD), scanning electron microscope(SEM), atomic force microscope(AFM) and spectrophotometer. XRD results show that the diffraction peaks of Mg2Si become stronger firstly, and then become weaker with the increase of Al doping amount. SEM and AFM results show that the crystallinity increases first and then decreases, grain size decreases, and the roughness increases first and then decreases with increasing doping level of Al. The indirect transition band gap of the doped films ranges from 0.423 eV to 0.495eV. The direct transition band gap ranges from 0.72 eV to 0.748 eV. The indirect and direct transition band gap are 0.53 eV and 0.833 eV before doping, respectively.

Key words: materials, Mg2Si thin films, Al doping, optical band gap, microscopy

WANG Shanlan1, LIAO Yangfang1,2, FANG Di1, WU Hongxian1, XIAO Qingquan1, YANG Yunliang1, XIE Quan1. Preparation and optical band gap of Al doped Mg2Si thin films[J]. Chinese Journal of Quantum Electronics.

References

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