Simulation Study Of Ⅲ-V GaAs-based Compound Semiconductor Solar Cell

As a new type of energy source, solar power is environmentally friendly and can be easily obtained. It is very important for people to solve the energy shortage crisis and derived environmental problems. Up to now, due to the high efficiency of GaAs solar cell (with regards to the conversion efficiency, the more the number of junctions is, the higher the efficiency, even up to 50% has been expected in theory), it has been paid more attention.After briefly describing the research background and development of GaAs solar cell, its work principle, optical and electrical characteristics are then introduced. Besides, the usage of simulation software Crosslight APSYS, some relevant equations and models are also given in a short introduction. By utilizing software Crosslight APSYS to simulate the electrical properties and conversion efficiency of GaAs solar cell, a detailed analysis of the result is provided.Firstly, this thesis provides a detailed simulation process of GaAs single junction solar cell. The program primarily changes the thickness, doping concentration and constitution of alloy material within tolerance limits, and then analyzes how these parameters influence Voc, Jsc, and Eff of the cell. After analyzing the new structure, then the parameter values are adjusted again, which primarily modifies the concentration of back surface field layer and buffer layer to about 1×1018cm-3 (actual process level). Finally, we acquire the efficiency of 26.48% (enhanced by 11% with respect to original structure, and the EQE is about 90%), indicating the purpose of improving the efficiency has been achieved. On top of that, this work also studies the suitable materials of BSF and Window layer, and the results indicate InGaP and AlGaAs are both appropriate.Then, after a short description of InGaP/GaAs dual junction solar cell, the initial structural values are modified: for one thing, we increase the general concentration of the cell. And for another, we modify the thickness of cap layer, from 0.5μm to 0.1μm, and an enhancement of one order of magnitude of concentration is input. Finally, the efficiency of dual junction cell is up to 35.16% (while the efficiency of the original structure is 28.79%). The result meets our expectation. Lastly, a detailed summary is given.