Effect of thickness: as case study of electrodeposited CdS in Cds/CdTe based photovoltaic devices

The effect of electrodeposition technique on CdS thickness incorporated in CdS/CdTe-based solar cell has been investigated using all-electrodeposited g/FTO/n-CdS/n-CdTe/p-CdTe multilayer device configuration. The optical, morphological and structural properties of the electroplated CdS were investigated for CdS thicknesses between 50nm and 200 nm. The observed CdS bandgap ranges between 2.42 and 2.46 eV. The morphological analysis shows full coverage of underlying g/FTO substrate for all CdS thicknesses except for the 50 nm which shows the presence of gap in-between grains. The structural analysis shows a preferred orientation of H(101) for all the CdS thicknesses except the 50 nm thick CdS which shows either a weak crystallinity or an amorphous nature. The fabricated solar cell shows a maximum conversion efficiency of ~11% using CdS thickness ranging between 100 and 150 nm. These results show that although low CdS thickness is desirable for photovoltaic application, the effect of nucleation mechanism of deposition technique should be taken into consideration.