Polycrystalline thin film n-Zn0.35Cd0.65S/(p)-CuGa0.25In0.75Se2 heterojunctions were fabricated and the current density-voltage, capacitance-voltage and spectral response characteristics of the junctions were studied. The heterojunction was illuminated in the back-wall configuration and an open-circuit voltage of 425 mV, a short-circuit current density of 30 mA cm(-2) and an electrical conversion efficiency of 8.8% have been obtained for a cell with an active area of 1 cm(2) under a solar input of 85 mW cm(-2).