A study of vapor CdCl_2 treatment by CSS in CdS/CdTe solar cells

摘要

We report the effect of CdCl_2 vapor treatment on the photovoltaic parameters of CdS/CdTe solar cells. Vapor treatment allows combining CdCl_2 exposure time and annealing in one step. In this alternative treatment, the CdS/CdTe substrates were treated with CdCl_2 vapor in a close spaced sublimation (CSS) configuration. The substrate temperature and CdCl_2 powder source temperature were 400℃. The treatment was done by varying the treatment time (t) from 15 to 90 min. Such solar cells are examined by measuring their current density versus voltage (J-V) characteristics. The open-circuit voltage (F_(oc)), short circuit current density (J_(sc)) and fill factor (FF) of our best cell, fabricated and normalized to the area of 1 cm~2, were V_(oc) = 663 mV, J_(SC) = 18.5 mA/cm~2 and FF = 40%, respectively, corresponding to a total area conversion efficiency of η = 5%. In cells of minor area (0.1 cm~2) efficiencies of 8% have been obtained.