ZnS1−xTex-based Schottky photodiodes have been fabricated on various substrates using the molecular beam epitaxy technique. The photovoltage output of these photovoltaic devices is determined using Fourier transform interferometric spectroscopy. The results show that these devices (withTe<10&percent;) are highly sensitive in the ultraviolet but are visible blind. An external quantum efficiency of over 50&percent; has been achieved on a device grown on a GaP substrate and over 40&percent; on a Si substrate. ©1997 American Institute of Physics.