中国物理B ›› 2018, Vol. 27 ›› Issue (2): 27802-027802.doi: 10.1088/1674-1056/27/2/027802

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

Optically induced abnormal terahertz absorption in black silicon

Dong-Wei Zhai(翟东为), Hai-Ling Liu(刘海玲), Xxx Sedao, Yu-Ping Yang(杨玉平)   

  1. 1. School of Science, Minzu University of China, Beijing 100081, China;
    2. Labo Hubert Curien, University of Lyon, France
  • 收稿日期:2017-07-07 修回日期:2017-10-08 出版日期:2018-02-05 发布日期:2018-02-05
  • 通讯作者: Yu-Ping Yang E-mail:ypyang_cun@126.com
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11574408, 11504439, 61627814, and 61675238), the National Key Research and Development Program of China (Grant No. 2017YFB0405402), the National Instrumentation Program of China (Grant No. 2012YQ14000508), and the Young-talent Plan of State Affairs Commission, China (Grant No. 2016-3-02).

Optically induced abnormal terahertz absorption in black silicon

Dong-Wei Zhai(翟东为)1, Hai-Ling Liu(刘海玲)1, Xxx Sedao2, Yu-Ping Yang(杨玉平)1   

  1. 1. School of Science, Minzu University of China, Beijing 100081, China;
    2. Labo Hubert Curien, University of Lyon, France
  • Received:2017-07-07 Revised:2017-10-08 Online:2018-02-05 Published:2018-02-05
  • Contact: Yu-Ping Yang E-mail:ypyang_cun@126.com
  • About author:78.47.jh; 73.63.-b; 42.65.Re
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos. 11574408, 11504439, 61627814, and 61675238), the National Key Research and Development Program of China (Grant No. 2017YFB0405402), the National Instrumentation Program of China (Grant No. 2012YQ14000508), and the Young-talent Plan of State Affairs Commission, China (Grant No. 2016-3-02).

摘要: The absorption responses of blank silicon and black silicon (silicon with micro/nano-conical surface structures) wafers to an 808-nm continuous-wave (CW) laser are investigated at room temperature by terahertz time-domain spectroscopy. The transmission of the blank silicon shows an appreciable change, from ground state to the pump state, with amplitude varying up to 50%, while that of the black silicon (BS) with different cone sizes is observed to be more stable. Furthermore, the terahertz transmission through BS is observed to be strongly dependent on the size of the conical structure geometry. The conductivities of blank silicon and BS are extracted from the experimental data with and without pumping. The non-photo-excited conductivities increase with increasing frequency and agree well with the Lorentz model, whereas the photo-excited conductivities decrease with increasing frequency and fit well with the Drude-Smith model. Indeed, for BS, the conductivity, electron density and mobility are found to correlate closely with the size of the conical structure. This is attributed to the influence of space confinement on the carrier excitation, that is, the carriers excited at the BS conical structure surface have a stronger localization effect with a backscattering behavior in small-sized microstructures and a higher recombination rate due to increased electron interaction and collision with electrons, interfaces and grain boundaries.

关键词: terahertz spectroscopy, black silicon, ultrafast phenomena

Abstract: The absorption responses of blank silicon and black silicon (silicon with micro/nano-conical surface structures) wafers to an 808-nm continuous-wave (CW) laser are investigated at room temperature by terahertz time-domain spectroscopy. The transmission of the blank silicon shows an appreciable change, from ground state to the pump state, with amplitude varying up to 50%, while that of the black silicon (BS) with different cone sizes is observed to be more stable. Furthermore, the terahertz transmission through BS is observed to be strongly dependent on the size of the conical structure geometry. The conductivities of blank silicon and BS are extracted from the experimental data with and without pumping. The non-photo-excited conductivities increase with increasing frequency and agree well with the Lorentz model, whereas the photo-excited conductivities decrease with increasing frequency and fit well with the Drude-Smith model. Indeed, for BS, the conductivity, electron density and mobility are found to correlate closely with the size of the conical structure. This is attributed to the influence of space confinement on the carrier excitation, that is, the carriers excited at the BS conical structure surface have a stronger localization effect with a backscattering behavior in small-sized microstructures and a higher recombination rate due to increased electron interaction and collision with electrons, interfaces and grain boundaries.

Key words: terahertz spectroscopy, black silicon, ultrafast phenomena

中图分类号:  (Coherent nonlinear optical spectroscopy)

  • 78.47.jh
73.63.-b (Electronic transport in nanoscale materials and structures) 42.65.Re (Ultrafast processes; optical pulse generation and pulse compression)