COMPUTER-SIMULATION OF CDTE ELECTRODEPOSITION

Following the simple kinetic model, based on the Butler-Volmer equatio n, developed by Engelken and Van Doren, a computer simulation has been performed of CdTe electrodeposition at 160-degrees-C from a special e thylene glycol-based bath containing CdCl2 (1 M), TeCl4 (0.01 M) and K I (0.3 M). From the fitting of the experimental data, the values of th e thermodynamic, kinetic and mass transport parameters of the electrod eposition process were obtained. Other simulations in which the influe nce of Cd and Te concentrations in the electrolyte has been analysed p roved that the given bath composition has been optimized to obtain ele ctronic-grade CdTe over a wide range of deposition potentials (more th an 50 mV around the point of perfect stoichiometry). They also showed that, as a consequence of the high ratio between the Cd and Te concent rations in solution, the potential ot perfect stoichiometry is less ne gative than the Cd Nernst potential, so that Cd underpotential deposit ion is possible. The results have been discussed within the framework of those obtained by Engelken and Van Doren in aqueous solution.