• Effect of pulse repetition rate on silicon wafer modification by four-beam laser interference

      Zhao, Le; Wang, Zuobin; Li, Wenjun; Yu, M.; Zhang, Z; Xu, J.; Yu, Y.; Weng, Z.; Li, S; Maple, Carsten; et al. (IEEE, 2013-08)
      This paper discusses the effect of pulse repetition rates on silicon wafer modification by four-beam laser interference. In the work, four-beam laser interference was used to pattern single crystal silicon wafers for the fabrication of dots, and different laser pulse repetition rates were applied to the process in the air. The results were obtained from 10 laser exposure pulses with the single laser fluence of 283mJ/cm2, the pulse repetition rates were 1Hz, 5Hz and 10Hz, the laser wavelength was 1064nm and the pulse duration 7-9ns. The results have been observed using a scanning electron microscope (SEM) and optical microscope. They indicate that the laser pulse repetition rate has to be properly selected for the fabrication of the structures of dots using four-beam laser interference.
    • Superhydrophobic dual micro- and nanostructures fabricated by direct laser interference lithography

      Li, Wenjun; Wang, Zuobin; Wang, Dapeng; Zhang, Ziang; Zhao, Le; Li, Dayou; Qiu, Renxi; Maple, Carsten; University of Bedfordshire; Changchun University of Science and Technology (Society of Photo-optical Instrumentation Engineers (SPIE), 2014)
      A method for the fabrication of highly ordered superhydrophobic dual micro- and nanostructures on silicon by direct laser interference lithography (LIL) is presented. The method offers its innovation that the superhydrophobic dual micro- and nanostructures can be fabricated directly by controlling the process of four-beam laser interference and the use of hydrofluoric acid (HF) to wipe off the silica generated during the process. Different laser fluences, exposure durations, and cleanout times have been investigated to obtain the optimum value of the contact angle (CA). The superhydrophobic surface with the CA of 153.2 deg was achieved after exposure of 60 s and immersion in HF with a concentration of 5% for 3 min. Compared with other approaches, it is a facile and efficient method with its significant feature for the macroscale fabrication of highly ordered superhydrophobic dual micro- and nanostructures on silicon.