Ea. Meulenkamp et Lm. Peter, MECHANISTIC ASPECTS OF THE ELECTRODEPOSITION OF STOICHIOMETRIC CDTE ON SEMICONDUCTOR SUBSTRATES, Journal of the Chemical Society. Faraday transactions, 92(20), 1996, pp. 4077-4082
Citations number
26
Categorie Soggetti
Chemistry Physical","Physics, Atomic, Molecular & Chemical
The kinetics of the electrodeposition of CdTe from an aqueous solution
containing HTeO2+ and Cd2+ have been studied using metallic (glassy c
arbon) and semiconductor (GaAs, CdS and Si) substrates. At metal elect
rodes, an almost diffusion-limited deposition current is often observe
d, and the deposit generally contains substantial amounts of elemental
Te. At semiconductor electrodes, on the other hand, the deposition cu
rrent is kinetically limited under identical conditions, and the CdTe
film can be of very good quality. The origin of this marked difference
has been investigated by comparing the influence of pH and the Cd2+/H
TeO2+ concentration ratio at both types of substrates. At semiconducto
r electrodes, it appears that a low surface electron concentration lea
ds to kinetically limited Te(IV) reduction if the concentrations of SO
42- and Cd2+ are high and the proton concentration is low. This low su
rface electron concentration cannot be obtained at metallic substrates
. Combination of optimised solution composition and correct choice of
semiconductor substrate allows definition of conditions for the growth
of stoichiometric CdTe.