| As one of the most important semiconductor material, silicon is widely used in the production of silicon-based semiconductor devices and photoelectric devices, which possesses the advantages of simple purification, easy doping and high temperature resistance. However, on account of the high light reflection from the visible band to the infrared band and its indirect band gap, the response sensitivity and light conversion efficiency are greatly reduced, which limit the application of silicon from the visible to the infrared band. Considering that the high-speed development of the modern information society demands more for the performance of silicon photoelectric and semiconductor devices, the researchers are constantly exploring the new ways of the modified crystalline silicon material. Taking advantage of femtosecond laser pulses with the excellent characteristics of short duration, high instantaneous power and accurate refocusing, this paper used it to irradiate the crystalline silicon surface for the modified silicon with the sub-micrometer structure and studied its unique physical and chemical properties.The sub-micrometer structured silicon was fabricated by femtosecond laser pulses with the central wavelength of 800 nm and the repetition rate of 10 Hz.With the help of fluorescence spectrophotometer, energy dispersive spectroscopy and Fourier transform infrared spectroscopy, the interaction mechanism between femtosecond laser pulses and monocrystalline silicon was preliminary studied.All the results demonstrated that the orange peak PL(at 603 nm) and the red band PL(near 680 nm) come from the suboxides(Si Ox) and recombination of the quantum confinement effect, respectively. And the oxygen element plays an important role in the photoluminescence.Meanwhile, in order to further study the influence of the oxygen element to the formation of sub-micrometer structure, the femtosecond laser pulses(repetition rate of 1 k Hz and central wavelength 800 nm) was used to irradiate the monocrystalline silicon. Under the deionized water and air, different sub-micrometer structures were generated bychanging the scanning speeds and energy intensities. The measurements showed that the visible photoluminescence reaches the strongest, only when the surface microstructure depth is not too deepand the shallow low oxide Si Ox is intensive. Besides, the different interaction mechanisms between femtosecond laser pulses and monocrystalline silicon at different energy intensities were explored, and the sub-micrometer structure can be controlled by changing the experiment parameters of femtosecond laser pulses.With the preparation of the sub-micrometer structures on the monocrystalline silicon surface by femtosecond pulse laser irradiation and the study of its characterization, the photoluminescence mechanism was in-depth explored, while the interaction between femtosecond laser pulses and crystalline silicon was better understood for the preparation of more high-performance silicon-based photoelectric devices. |
