Photovoltaic properties of close-space sublimated CdTe solar cells

Abstract

CdS/CdTe solar cells were fabricated by close-space sublimation with a screen-printed Te-rich CdTe source and their photovoltaic properties were investigated by varying the substrate temperature, cell area, and thicknesses of CdTe and ITO layers. The resistivity of CdTe layers employed in this study was 3 x 10(4) Omega cm. The optimum substrate temperature and thickness for CdTe deposition were 600 degrees C and 5 mu m, respectively. The CdTe bulk resistance degraded the cell performance above 6 mu m. As the cell area increased the V-oc remained almost constant, while the J(ae) and FF were strongly degraded because of the increase of the lateral resistance of the ITO layer. The optimum thickness of the ITO layer in this study was 300-450 nm. In this experiment we obtained an efficiency of 9.4% in the 0.5 cm(2) cells. The series resistance of the cell should be further reduced to increase the fill factor and improve the efficiency. (C) 1998 Elsevier Science Ltd. All rights reserved.