Nanocrystalline Silicon Optical Frequency Conversion Enhancements And Crystal Silicon Photoelectric Conversion Efficiency

Si light emission is vital for the integrated optoelectronics based on modern Si technologies. The fabrication of silicon nanocrystals embedded in silicon dioxide (nc-Si:SiO2) is an important method for the enhancement of silicon luminescence. What is more, photoluminescence (PL) conversion of nc-Si:SiO2 by absorbing ultraviolet lights and emitting visible ones can be used to improve the efficiency of crystalline Si solar cells.Firstly, a multilayered SiO/Si sample structure is studied to acquire strong photoluminescence (PL) emission via modulating excess Si concentration. PL intensity of the brightest sample is found to be～5 times that of monolayer sample. Based on TEM and EDX, and we find that the concentration of Si nanoparticles in this sample is enhanced by a large scale.Secondly, we employ photoluminescence conversion mechanisms of nc-Si:SiO2 to convert the ultraviolet (UV) lights into the visible ones so that the absorbed light flux of solar cell can be increased. On one hand, crystalline Si solar cells have a poor absorption in the UV part of the solar spectrum, while good in the red/infrared part. On the other hand, no matter AM1.0 or AM1.5, the amount of UV light takes a large part of the solar spectrum. Therefore, this PL emission feature can be used to improve the performance of crystalline Si solar cells.