| Compensated silicon is reported as a cost-effective material for solar cells.In this work,the n-and p-type compensated silicon are investigated when using in directional solidification,ingot casting,crystal growth,characterization of wafers and fabrication of solar cells.After exhaustively investigation,the researching findings are outlined below:(1)For promoting the industrialization of compensated silicon,we made an ingot casting furnace and an equipment for purification by directional solidification.I served as a principal in charge in this group.(2)The effective segregation coefficients of the most common four impurities:Phosphorus,Boron,Germanium and Carbon are determined based on lots of silicon ingots.(3)Deviations are found between Klaassen's model and measured carrier mobilities.We found the origin of the deviation,and corrected it.(4)The relations between uncompensated and compensated wafers with identical performances are found.In addition,this relation is supported by our solar cell experiment.(5)Judging by the resistivity,the optimized starting resistivity for n-type compensated Cz silicon is 5.5 ?·cm;the optimized concentration of boron is 0.8 × 1016 cm-3.A two-step method is used to improve the uniformity of resistivity for the n-type compensated Cz silicon.The lower carrier lifetime in compensated silicon is owing to the very high concentration of dopants and oxygen.(6)The fabricating technology of aluminum-alloyed back junction n-type silicon solar cells were investigated.A lowest temperature-coefficient had been observed for aluminum-alloyed back junction solar cells using compensated silicon.(7)The software of "AFORS-HET" was used to simulate the HIT solar cells with compensated silicon as base layer.We achieved the best efficiency of 20.2%with n-type compensated silicon wafers. |
PDF Full Text Request