Cd-In-Te films were electro-deposited potentiostatically over SnO2:F coated glass substrates from aqueous acidic solutions containing CdSO4, InCl3 and TeO2 at 85 degreesC. Cyclic voltammetric studies were carried out to study the growth process and the potential range for ternary Cd-In-Te thin film deposition. Crystalline structure and surface morphological studies were carried out and correlated with the deposition potential. The deposited film showed cubic structure having a high degree of (I 11) orientation. Optical transmission studies showed a direct band structure and the band gap of the deposited film change with the deposition potential. A typical decrease from 1.2 to 1.1 eV in the optical band gap was observed on increasing the cathodic deposition potential from -0.5 to -0.54 V (SCE). (C) 2002 Elsevier Science B.V. All rights reserved.