The performance of CuInSe2/CdS solar cells fabricated by the sandwich structure technique

The solar cell structure is based upon a heterojunction of p-type CulnSe2 (CIS) and n-type CdS or mixed CdZnS. The use of a mixed CdZnS layer is reported to increase the open circuit voltage. The cells have been fabricated using the stacked elemental layer (SEL) technique for the fabrication of CIS thin films. The effect of layer resistivities on the performance of the device has been studied. The photoresponse was also determined and an essentially flat region between 0.6 and 1.0 mu m was found. Dark and light I-V characteristics in ambient and different solar cell temperatures have been investigated. Capacitance-voltage-frequency relationships were determined. A photovoltaic effect was observed with an ELH illumination (85 mW cm -2). Conversion efficiencies up to 5.2% were obtained. The results are discussed and recommendations for future work are suggested.