Formation of low resistance contacts to p-CdTe by annealing autocatalytically deposited Ni-P alloy coatings

A novel technology for forming low resistance ohmic contacts to p-CdTe has been developed. The technology is based on the autocatalytic deposition of Ni-P alloy coatings onto p-CdTe followed by an anneal to reduce the degree of supersaturation of P in Ni and to hence diffuse P into the CdTe. Energy dispersive X-ray analysis (EDAX) and X-ray diffraction data were used to monitor changes in the Ni-P during the annealing and contact resistance measurements made to assess the viability of the technology. The data are consistent with the in-diffusion of P into the CdTe and the specific contact resistivity reduced to 0.08-0.1 Ω · cm 2 for an optimum annealing temperature of 250°C. The contact technology has also been applied to the p-CdTe used in CdS/CdTe thin film solar cells with encouraging results.