QUASI-CONTINUOUS ELECTRODEPOSITION OF CDTE THIN-FILMS

Thin CdTe films of 4-6 cm(2) each were quasi-continuously deposited in a series of up to 10 experiments onto CdS/ITO/glass substrates at 85 degrees C in a membrane cell housing a four electrode assembly, The Cd and Te split anodic currents were regulated by an automatic current c ontrol unit connected to a potentiostat. The anolytic compartment with the less noble Cd electrode was separated by a cation exchange membra ne from the catholytic compartment containing the other electrodes. An olyte and catholyte were aqueous solutions of triethanolamine and diff erent amounts of [Cd(TEA)](2+) and TeO32-. Depositions were carried ou t for 45-90 min at a potential of -1050 mV vs. see (45 degrees C). As- deposited layers contained finely grained polycrystalline cubic and he xagonal CdTe. Thermal annealing at 400 degrees C in air and subsequent etching in K2Cr2O7/H2SO4 and N2H4 . H2O yielded cubic CdTe with a Te- rich surface according to x-ray diffraction and Raman scattering inves tigations. Au/CdTe/CdS/ITO test structures exhibited weak photoactivit y.