A Numerical Study on a c-Si(P) Substrate-Based Homo-Hetero Junction Solar Cell

Abstract

A homo-hetero junction solar cell made up of crystalline and amorphous silicon is investigated using AFORS-HET simulator. The ability of a homo-hetero junction cell to improve photoelectric behavior is well established. The study is carried out on a p-type crystalline silicon substrate which forms a shallow junction with n-type crystalline silicon. The addition of highly doped amorphous silicon at the top and bottom surfaces creates extra field, thus reducing the interface recombination and series resistances. The study includes the thickness variation of n-type amorphous silicon, n-type crystalline silicon, and p-type substrate, to find out the optimum result. Also, the effect on cell performances due to the variation of n-type amorphous silicon doping is performed. In comparison with a heterojunction with thin intrinsic layer (HIT) cell, homo-hetero junction is different in a way that it includes the additional crystalline silicon layer which actually enhances the field-effect passivation, thereby further reducing the series resistance and enhancing the fill factor to a greater extent. The excess amount of field also makes it less sensitive toward the interfacial defect states, and to prove it, we increase the defect states up to 102 times greater than that of a HIT cell. The calculated total recombination factor, Jo, is found to be as low as 3.45 fA/cm2. Finally, we achieved an efficiency of 28.33% with enhanced fill factor (FF) of 0.88.