Pulsed Plasma Deposition for CdTe solar cells and its up-scaling for large area applications

This work is aimed to demonstrate the advantages of using Pulsed Plasma Deposition (PPD) for the industrial production of CdTe based photovoltaic cells on large area substrates. The research consists, on one side, in optimizing the process of deposition and fabrication of (CdTe/CdS) solar cells with the aim to improve the efficiency, and on the other side much attention and work have been paid for demonstrating the scalability of the process towards industrialization. In this paper we demonstrate that the PPD, which shows several advantages for the production of thin films for applications in the photovoltaic field, is suitable for large area fabrication. In fact the PPD combines large deposition rates, and excellent film quality with the simplicity and versatility of the process. Moreover the relatively low cost of the equipments required for the production make of it a promising resource for the photovoltaic industry. PPD offers several advantages concerning its industrialization. Experimental tests show that using more than one source, the plasma plumes generate a uniform film on a wide area. The possibility to reach an high deposition rate, which is much larger than traditional sputtering and CVD techniques, permits to reduce the deposition time, so to obtain a higher productivity. At the same time, since the process temperature is lower compared to conventional techniques, the thermal budget is reduced with a consequent reduction of the related energy costs. We have fabricated ZnO/CdS/CdTe cells whose efficiency resulted in the 10% range showing the high potential of the technology