With the global economic development and population growth, the pollution problem caused by fossil energy is becoming more and more serious. People begin to explore alternatives to traditional energy. Solar energy is the most abundant and easily accessible renewable energy on the earth. Solar cell is a semiconductor device that directly uses solar energy to generate electricity through photoelectric conversion effect.
The comparison between the properties of band gap and indirect band gap semiconductor materials leads to the advantages of gallium arsenide in the preparation of solar cells. The design principle and advantages of multi junction laminated III-V solar concentrating cells are introduced. The effects of surface micro nano structures such as nanowires and nanocolumns based on gallium arsenide on the performance of solar cells are introduced.By adjusting the growth parameters, the axial and radial growth rates of GaAs nanowires are controllable. On this basis, GaAs nanowires with core-shell p-n structure are prepared by molecular beam epitaxy. At the same time, one-dimensional nano core-shell photovoltaic devices are obtained by exploring the lithography, shell etching and ohmic electrode preparation processes of GaAs one-dimensional nanostructures. The I-V test results show that, Under the simulated sunlight irradiation (am l.5g, 1 sun) t, the open circuit voltage voc-0.539, the short circuit current LSC = 10.374ma/cm2, the effective filling factor FF = 0.6796 and the efficiency is 38%.
In order to obtain the optimal conversion efficiency of nanowire array solar cells, the structure of GaAs axial pin junction nanowire array is optimized by simulation calculation. Firstly, the optical absorption characteristics of GaAs nanowire array are analyzed by three-dimensional finite-difference time-domain method, and its diameter, density and other structural parameters are optimized. The optical absorption of optimized GaAs nanowire array can reach 87.4%, The electrical performance of the cell is analyzed by using the electrical simulation module in sentaurus software package, and the axial pin junction structure is optimized according to the distribution of photogenerated carriers in the nanowires. Finally, the optimized power conversion efficiency of the solar cell can reach 17.6%. The analysis results show that the surface recombination rate of GaAs nanowires can be reduced by passivation, The power conversion efficiency of the battery can be significantly improved, and the carrier recombination loss can be reduced by reducing the volume of the highly doped region at the top of the nanowire, so as to improve the battery efficiency