LOW SUBSTRATE TEMPERATURE DEPOSITED CdTe SOLAR CELLS WITH AN ALTERNATIVERECRYSTALLIZATION PROCESS

In this paper we describe a vacuum evaporation deposition process where the substrate temperature doesnot exceed 450°C and we study a recrystallization process which avoids the use of CdCl2, which is a carcinogenicmaterial, compared with the standard procedure. In our process CdS and CdTe are deposited at pressures of 10-6 mbar inthe same chamber by thermal evaporation and with substrate temperature of 150°C and 340°C, respectively. TheCdTe/CdS/TCO stacks are then put in a quartz chamber and, after having previously pumped the chamber down to 10-5mbar, a controlled mixture of argon and chlorine containing gas are fluxed with a substrate temperature in a rangebetween 400°C and 450°C. The morphological properties of the single layers are studied by X-ray diffraction (XRD),atomic force microscopy (AFM) and the electrical properties of the finished devices will be presented by means ofcurrent-voltage (I-V) measurements.