Investigation of electrodeposited CdTe thin films for solar cell development

We report the growth of CdTe thin films using a wet-chemical electrochemical technique in an aqueous bath. The effect of bath temperature is investigated in detail on the various properties of the sample and the optoelectronic performance of the solar cell devices. A three-electrode technique was employed to deposit the samples at - 0.7 V concerning the Ag/AgCl reference electrode optimized by cyclic voltammetry measurements. The sample annealed at 450 degrees C for 20 min exhibited a polycrystalline cubic crystal structure of CdTe with an optical energy bandgap of similar to 1.45 eV. The Raman analysis reveals the growth of highly polycrystalline CdTe. All samples were highly compact and well-adherent to the substrate without pinholes. The annealed sample grown at a bath temperature of 50 degrees C exhibited a large globular grain size of similar to 1 mu m. Furthermore, the stoichiometric (50:50) growth of Cd and Te was confirmed using EDAX for the sample grown at a bath temperature of 50 degrees C. A typical solar cell device, glass/FTO/CdS/CdTe/Au, was measured under dark and illuminated conditions with an input intensity of 100 mW/cm(2) and showed a fill factor of similar to 50% and an efficiency of 2.65%. The solar cell parameters can be further improved by optimizing the surface treatment conditions using appropriate oxidizing and reducing reagents.

Automated summary

In this study, CdTe thin films were successfully grown using a wet-chemical electrochemical technique in an aqueous bath. The effect of bath temperature on the properties of the sample and the optoelectronic performance of the solar cell devices was investigated. The annealed sample exhibited a polycrystalline cubic crystal structure of CdTe with the desired grain size and stoichiometry. The solar cell device showed a relatively high fill factor and efficiency.