| The papers primary consists of three parts:1. The material choice of triple junction high-efficiency solar cells.Based on a great deal of investigating and studying on relational information, analyzing and comparing the properties of IV, III-V and II-VI semiconductors, ZnSe/GaAs/Ge, GaInP/GaAs/Ge, GaAlAs/GaAs/YP are several good groups of matching material for coverage of the solar spectrum , thereinto ZnSe/GaAs/Ge may be a optimal collocation. Their crystal structures all belong to face-centred cubic system. Their crystal lattice constant are 5.669, 5.653, 5.657A respectively, mismatch is less than 0.05 A. So they can form good heterogeneity single crystal compound. Energy gaps of ZnSe. GaAs and Ge equal to 2.61, 1.43, 0.67 eV respectively, and they distribute equably in high, middle and low section of total solar spectrum.2. The external quantum efficiency (QE) of ZnSe p-njunction and Current-matching of ZnSe/GaAs/Ge triple-junction tandem photoelectric cellsWe have obtained a progress to raise the P-type doping concentration up to 10 18 cm-3through adding a little bit of Tellurium, so that to make the ZnSe p-n junction becomes possible and interesting. ZnSe p-n junction sample was made by Molecular Beam Epitaxy (MBE) technology, and its external quantum efficiency (QE) curve has been measured. The spectrum absorption of ZnSe p-n junction starts from 476nm, and photo-flux of wavelength less than 476nm is 19% of the solar energy under AM1.0. Its half-high-wide response range is 365-450nm, the peak value is located at 400nm. The half-high-wide response range of GaAs p-n junction is 410-880nm, and half-high-wide response range of Ge p-njunction is 900-1650nm. The half-high-wide of response ranges of ZnSe, GaAs and Ge p-n junction connect with each other well. Under AM1.5, the solar cell can cover 95% of the total solar spectrum, its theory efficiency can achieve 56% .The performance was analyzed by substituting the ZnSe p-n junction with the Au/i-ZnSe/n-ZnSe(MIS structure) Schottky junction. The improved ZnSe/GaAs/Ge tandem cells have the advantages of high open circuit voltage, high covering ratio for solar spectrum, better current-matching, and simpler making technique.n-ZnSe/i-ZnSe/p+-GaAs/n-p-Ge tandem structure has the advantages of better radiation hardness, and simpler making technique.3.The calculating of electric field of uneven-doped and influence for solar cells conversion efficiency.The uneven-doped in solar cell film, the photovoltaic characters can be improved. The uneven-doped electric field in top region can reduce surface compound rate. Theuneven-doped electric field in base region compels the minority carrier move into p-n junction, so it can reduce losing of minority carrier compound. The saturation current is decreased due to diffuse term value of uneven-doped electric field. So the open voltage can be improved.The uneven-doped electric field of under thermo-balance is calculated using Runge-Kutta-Vemer method. And optimize doped project can be chosen by the method.
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