Realization and Characterization of ZnO/n-Si Solar Cells by Spray Pyrolysis

Indium doped zinc oxide (ZnO: In) thin films have been prepared using spray pyrolysis technique. The used spray solution has a molarity of 0.2 M of chemical pure hydrated zinc acetate (Zn (CH3CO2)2H2O) and 2% by weight of indium chloride (InCl3). Zinc acetate was dissolved in a mixture of bidistilled water and methyl alcohol (80%H2O:20% CH3OH). The ZnO/n-Si solar cells have been realized by depositing the ZnO: In on Si wafers separated by a thin interfacial SiO2 layer ameliorating the barrier height. The realized ZnO /n-Si solar cells shows rapid degradation of the cell performance with storage time in dark. This could be attributed to the porosity of ZnO films which allows the oxygen to diffuse through it increasing the thickness of the interfacial SiO2 layer due to the reaction with Si. The degraded characteristics of ZnO/n-Si junction solar cells can be minimized by depositing a conducting layer of indium tin oxide (ITO) as a barrier layer on ZnO/n-Si. A thin layer of ITO is deposited on ZnO films to suppress the oxygen diffusion to Si wafer. The best output parameters obtained for ITO/ZnO-nSi cells are; open circuit voltage VOC = 0.44 V, short circuit current density JSC =20 mA/ cm2 , fill factor FF =0.6 and efficiency η =5.28%.