Investigation of sulphur diffusion at the CdS/CdTe interface of thin-film solar cells
Diffusion of atoms across the CdS/CdTe interface during post-deposition annealing is thought to have an important effect on the performance of CdS/CdTe-based solar cells. Thin-film solar cell samples were annealed at 400°C for three different times. The samples were etched sequentially in a bromine/methanol solution and then examined with Auger depth profiling and X-ray diffraction. Profiling showed the as-deposited samples to have little or no interfacial mixing, but annealing even for a short time caused diffusion of sulphur into the CdTe material. As the annealing times lengthened, the concentration of sulphur in the CdTe increased. X-ray diffraction measurements indicated that the CdS layer rapidly crystallized into its hexagonal Greenockite modification, but with lattice parameters increased by 0.8%. This changed little with annealing time. The CdTe near the interface appeared to have a modified but well-defined cubic structure with respect to reference CdTe, as indicated by splitting of the diffraction peaks, denoting the growth of a CdTexSy interfacial layer. This layer increased in thickness with annealing time and most probably has a stoichiometry within the range CdTeS(0.04)-CdTe(0.88)S(0.12).
Bibliographic Reference: An article published in: Surface and Interface Analysis Volume 33, Issue 10-11, (2002), pp.825-829
Availability: This article can be accessed online by subscribers at: http://dx.doi.org/10.1002/sia.1459
Record Number: 200316038 / Last updated on: 2003-03-13
Original language: en
Available languages: en