Fabrication And Properties Of GaAs-based Quantum Dots Solar Cells

GaAs based solar cells have a lot of advantages, such as high photoelectric conversion efficiency, good radiation-resistance and good performance at high temperatures, etc., and are promising in utilizing solar energy. In this thesis. InAs/GaAs quantum dot solar cells are fabricated by molecular beam epitaxy. We discussed the spectral absorbance properties of the quantum dot solar cells with different sizes.In this thesis, we studied the QDs growth conditions, optimizing such parameters as growth temperature and growth rate. The QDs size and density depended critically on the growth temperature and the deposition thickness of the InAs quantum dots. Optimized growth conditions were obtained experimentally by using antimony surfactant-mediation. We optimized the growth condition of InAs/GaAs quantum dots to fabricate two kinds of quantum dots with similar density but with different sizes. We report the fabrication of InAs/GaAs quantum dot solar cells with enhanced photocurrent compared to a solar cell grown without QDs. It was shown that it is feasible to expand the scope of material spectral response up to1.24μm and to improve light absorption by changing the size of the quantum dots. These results are of major significance to the design and fabrication of high efficiency quantum dot solar cells.