Fig. 1. Experimental setup for femtosecond laser processing of micro/nano structures on material surfaces

Fig. 2. Comparative diagram of samples processed with different parameters

Fig. 3. SEM images magnified 2k times of processed samples in four different gas environments. (a) Air; (b) vacuum; (c) nitrogen; (d) sulfur hexafluoride. (e)-(f) indicate SEM images magnified 5k times of rectangular box areas in (a)-(d) respectively

Fig. 4. SEM images magnified 2k times of prosessed samples tilted 45° in four different gas environments. (a) Air; (b) vacuum; (c) nitrogen; (d) sulfur hexafluoride. (e)-(f) indicate SEM images magnified 5k times of rectangular box areas in (a)-(d) respectively

Fig. 5. XPS test analysis of prosessed sample surface in different gas environments

Fig. 6. Comparison of reflectance and transmittance in near-infrared range between original wafer and processed sample. (a) Reflectance; (b) transmittance

Fig. 7. Schematic diagram of light absorption for micro/nano structures of sample

Fig. 8. Diagram of electrode setup used in experiment

Fig. 9. I-V curves of sample under dark state and 50 mW light illumination conditions. (a) Under dark state; (b) under 50 mW light illumination