An ultraviolet-sensitive photodetector based on the metal-semiconductor-metal structure has been fabricated on a chemical-vapor-deposited diamond thin film grown on a silicon substrate. Device processing techniques employed include maskless laser writing lithography, image reversal processing and sacrificial layer inclusion, which resulted in devices with an electrode finger separation of only 2.5 &mgr;m. This allows for a low operating voltage of only 5 V, which is very much lower than what has been achieved so far. ©1998 American Institute of Physics.