Solar Energy Materials and Solar Cells, Vol.75, No.1-2, 203-210, 2003
Back contact formation usingCU(2)Te as a Cu-doping source and as an electrode in CdTe solar cells
Cu2Te was utilized as a Cu source for p(+) doping in CdTe and as a primary back contact material in CdTe solar cells. A 60nm-thick Cu2Te layer was deposited on CdTe film by evaporating Cu2Te and the samples were annealed at various temperatures. An amorphous layer was found at the Cu2Te/CdTe interface, while the Cu2Te has both orthorhombic and hexagonal phases. Annealing at 200degreesC completely crystallized the amorphous interlayer and enhanced the transformation of orthorhombic phase into hexagonal phase that has a coherent interface with CdTe. A good p(+) contact was formed at 180degreesC annealing, where the series resistance of CdTe cells was a minimum of 0.5 Ohm(.)cm(2) and the fill factor and open-circuit voltage were significantly improved. With the good p(+) contact, it is possible to determine the exact dopant profile at the CdS/CdTe junction. (C) 2002 Published by Elsevier Science B.V.