Polycrystalline Thin-Film Cadmium Telluride Solar Cells Fabricated by Electrodeposition: Final Technical Report, 20 March 1995-15 June 1998

This report summarizes work performed by the Colorado School of Mines Department of Physics under this subcontract. Based on the studies conducted, researchers increased the efficiency of the cells with electrodeposited CdTe and CBD CdS by 3% on average. The improvement came from 1) optimization of CdS initial thickness taking into account CdS consumption of CdTe during the CdTe/CdSpost-deposition treatment; optimization of CdS post-deposition treatment with CdCl2 aimed at prevention of Te diffusion into CdS and improvement of the CdS film morphology and electronic properties. That led to a considerable increase in short circuit current, by 13% on average. 2) Optimization of CdTe thickness and post-deposition treatment which led to a significant increase in Voc, by approx.70 mV. The highest Voc obtained exceeded 800 mV. 3. Development of a ZnTe:Cu/Metal back contact processing procedure that included selection of optimal Cu content, deposition regime and post-deposition treatment conditions. The cell stability was measured on exposure to accelerated stress conditions. Preliminary studies of some new approaches to improvement of CdS/CdTe structure were conducted.