Impact of film thickness in laser-induced periodic structures on amorphous Si films

Liye Xu; Jiao Geng; Liping Shi; Weicheng Cui; Min Qiu

doi:10.1007/s12200-023-00071-6

Impact of film thickness in laser-induced periodic structures on amorphous Si films

Front Optoelectron. 2023 Jun 20;16(1):16. doi: 10.1007/s12200-023-00071-6.

Authors

Liye Xu^{1

2

3

4}, Jiao Geng^{5

6}, Liping Shi^{2

4

7}, Weicheng Cui^{8

9}, Min Qiu^{10

11}

Affiliations

¹ College of Optical Science and Engineering, Zhejiang University, Hangzhou, 310058, China.
² Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China.
³ Key Laboratory of Coastal Environment and Resources of Zhejiang Province (KLaCER), School of Engineering, Westlake University, Hangzhou, 310024, China.
⁴ Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, 310024, China.
⁵ Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China. gengjiao@westlake.edu.cn.
⁶ Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, 310024, China. gengjiao@westlake.edu.cn.
⁷ Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, 430074, China.
⁸ Key Laboratory of Coastal Environment and Resources of Zhejiang Province (KLaCER), School of Engineering, Westlake University, Hangzhou, 310024, China. cuiweicheng@westlake.edu.cn.
⁹ Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, 310024, China. cuiweicheng@westlake.edu.cn.
¹⁰ Key Laboratory of 3D Micro/Nano Fabrication and Characterization of Zhejiang Province, School of Engineering, Westlake University, Hangzhou, 310024, China. qiumin@westlake.edu.cn.
¹¹ Institute of Advanced Technology, Westlake Institute for Advanced Study, Hangzhou, 310024, China. qiumin@westlake.edu.cn.

Abstract

We report self-organized periodic nanostructures on amorphous silicon thin films by femtosecond laser-induced oxidation. The dependence of structural periodicity on the thickness of silicon films and the substrate materials is investigated. The results reveal that when silicon film is 200 nm, the period of self-organized nanostructures is close to the laser wavelength and is insensitive to the substrates. In contrast, when the silicon film is 50 nm, the period of nanostructures is much shorter than the laser wavelength, and is dependent on the substrates. Furthermore, we demonstrate that, for the thick silicon films, quasi-cylindrical waves dominate the formation of periodic nanostructures, while for the thin silicon films, the formation originates from slab waveguide modes. Finite-difference time-domain method-based numerical simulations support the experimental discoveries.

Keywords: Laser nanofabrication; Laser-induced periodic surface structures (LIPSS); Quasi-cylindrical waves; Ultrafast optoelectronics.