Analysis of CdCl2 annealing process in CdTe/CdS solar cells

Potter, M.D.G.; Halliday, D.P.; Cousins, M.A.; Scheer, H.; McNelis, B.; Palz, W.; Ossenbrink, H.A.; Helm, P.

Analysis of CdCl2 annealing process in CdTe/CdS solar cells

Potter, M.D.G.; Halliday, D.P.; Cousins, M.A.; Scheer, H.; McNelis, B.; Palz, W.; Ossenbrink, H.A.; Helm, P.

Authors

M.D.G. Potter

Professor Douglas Halliday d.p.halliday@durham.ac.uk
Professor

M.A. Cousins

H. Scheer

B. McNelis

W. Palz

H.A. Ossenbrink

P. Helm

Abstract

A series of CdTe/CdS solar cells are subjected to CdCl2 anneals of varying lengths and then chemically bevelled and analysed by photoluminescence (PL) spectroscopy. Half of the samples were subjected to a physical polishing using 0.25 m diamond paste prior to bevelling in order to study the effects of back surface stress on the devices. Polishing was observed to create a PL peak at 1.48eV attributable to Y luminescence, and also to cause the suppression of the 1.55eV acceptor related peak. Regardless of polishing, a shift in position of the 1.43eV donor-acceptor pair peak, associated with chlorine donors and cadmium vacancy acceptor complexes, was observed in the more efficient cells, attributable to energy band gap reduction caused by sulphur diffusion into the CdTe at the interface. Temperature and intensity dependent PL have been used to further characterise the observed PL emission peaks. The PL data has been correlated with measurements of the electrical characteristics of the cells. Keywords: Photovoltaic -1: CdTe -2: Spectroscopy -3

Citation

Potter, M., Halliday, D., Cousins, M., Scheer, H., McNelis, B., Palz, W., …Helm, P. (2000). Analysis of CdCl2 annealing process in CdTe/CdS solar cells.