Excellent near-infrared response performance in p-CuS/n-Si heterojunction using a low-temperature solution method

Abstract

The solution method is recognized as the most promising type for the preparation of CuS particles because of the advantages of high yield and easy tuning. In this work, p-type CuS nanoparticles were synthesized by a low-temperature water bath method, and the effects of different copper sources, synthesis temperatures, and different raw material ratios on the preparation of CuS were investigated. The X-ray diffraction XRD results indicate that the prepared CuS is polycrystalline with a hexagonal structure. The optical data show that the bandgap of the prepared CuS is between 2.52-2.69 eV. SEM images show that the difference in copper source significantly affects the morphology of CuS particles. Based on the high optical absorption coefficient, p-CuS/n-Si heterojunction photodetectors were constructed from the synthesized CuS and n-Si wafers with an inverted pyramidal structure to investigate their photoresponse capability. The results show that under the irradiation of 980nm near-infrared light, it has a maximum responsivity of 0.493mA/W at 0V bias, indicating its good self-driven ability. At -5V bias, the maximum responsivity of 1.322 A/W and the switching ratio of 5171 show that p-CuS/n-Si heterojunction photodetectors have great potential to be used in the near-infrared detection field.