Microelectronics has made progress in the research of black silicon cells

Recently, research team Jia Rui of the Institute of Microelectronics of the Chinese Academy of Sciences has made new progress in the research of new black silicon batteries.

Black silicon has good light trapping characteristics and extremely low light reflectance (<1%). It has important industrial application prospects in high-efficiency, low-cost crystalline silicon cells and is a research hotspot in the world. At present, there are many bottlenecks in the efficiency improvement of black silicon solar cells. One of the main reasons is that the surface nanostructures are larger than the surface area, there is a high density of gaps between the nanostructures, resulting in poor carrier transport ability and poor electrode contact performance. The problem is that the good light trapping characteristics of black silicon cannot be fully used in high-efficiency crystalline silicon solar cells.

In view of the excellent photoelectric properties of ZnO nanowires and high carrier mobility, Jia Rui team innovatively introduced ZnO nanowires into black silicon solar cells, and laterally contacted ZnO nanowires were grown in the gap between silicon nanostructures. The laterally-contacted ZnO nanowires can promote lateral transport and collection of photo-generated carriers, effectively reducing the contact resistance and improving the cell efficiency. The test results of IV characteristics, spectral response and quantum efficiency of ZnO nanowire black silicon cells show that the insertion of ZnO nanowires does not change the good light trapping characteristics of black silicon cells and significantly improves the characteristics of electrode contact and carrier transport. This proves from a theoretical point of view that ZnO nanowires contribute to the improvement of the efficiency of black silicon cells. The ZnO material has low cost, simple preparation process, good process compatibility with the existing crystalline silicon cell process, and has broad application prospects. Jia Rui team is currently working to transfer this innovation and technology to efficient back contact and heterojunction back contact battery research.

The above research results have applied for national invention patents (patent application No. 2) and published in the February 2015 International Journal Applied Physics Letters (DOI: 10.1063/1.4907645), which has been highly evaluated by international peer experts. The project was funded by the National High-Tech Research and Development Program ("863" Program) and the assistance of China Yingli Green Energy Holdings Co., Ltd.