Abstract
In this research work, we investigated high efficiency grating solar cells by electrochemical etching with different etching parameters, etching solution and acid treatment. Since Dimethylformamide (DMF) solution which was used as the electrolyte for our earlier work has several serious health hazards, we replaced this electrolyte by Dimethl Sulfoxide (DMSO).Also we observed that the morphology of the pores formed on the silicon wafer depends on the etching time, current density, concentration of electrolyte and the resistivity of the wafer used.Grating solar cell which showed better performance in this study was fabricated with porous silicon structure obtained with an electrolyte of concentration 3M HF/DMSO, current density 3 mA/cm2 and an etching time ranging from 40 minutes to 60 minutes. The efficiency obtained with this condition was 8.587 % with a short circuit current density (Jsc) of 40.435 mA/cm2, and the open circuit voltage (Voc) of 0.534 V.For the further improvements of the performance of grating solar cell, we treated the porous silicon wafer with nitride acid (HNO3) for 10 days before p-n junction formation to get a thin passivation layer of SiO2. We found that the grating solar cells fabricated with acid treated samples showed higher efficiency of 15.503 % with very high short circuit current density (Jsc) of 53.445 mA/cm2 and open circuit voltage (Voc) of 0.579 V.