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Black silicon, which is characterized as numerous nanospikes induced on bulk silicon, has recently attracted great attention due to its fascinating photoelectric property. Compared with the traditional silicon-based photoelectric sensor, photoelectric sensors based on the black silicon doped with supersaturated chalcogens have shown both excellent photoelectric corresponding efficiency in the visible range and considerable optical absorption efficiency in the near infrared band due to the impurity energy-level introduced by the chalcogens element supersaturated doping. Nonetheless, the differences of surface morphology greatly affect the photoelectric efficiency of black silicon photoelectric sensors, which is quite difficult to control in practice. As one of the mainstream methods in black silicon fabrication, femtosecond laser etching exhibits the ability in manipulate different dimensionality and configurations and provide a clear and flexible research platform. Black silicon can be etched on traditional silicon-based photoelectric sensor with different size of surface morphology according to the size of surface thickness. In this work, by varying the etching energy density of the femtosecond laser, three kinds of black silicon samples with different surface morphology were obtained. At the same time, the surface morphology, size, visible-infrared absorptivity and photoelectric conversion efficiency of black silicon were characterized by scanning electron microscope, spectrophotometer and confocal Raman spectroscopy, etc. We got three sample characterization data, the minimum morphology depth of black silicon can be controlled at 2μm, the maximum visible light absorption efficiency can reach 90%, and the near-infrared absorption efficiency can reach 60% before annealing. Naturally, the photoelectric conversion efficiency has been proven to be significantly improved. Based on the observation of experimental results, it is an important step to understand the photoelectric characteristic of black silicon with different morphologies, which is the application of black silicon in different fields.
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