The growth, construction, and characterization of a high speed low temperature (LT)-GaAs metal-semiconductor-metal (MSM) photodetector grown by the photoassisted metalorganic chemical vapor deposition (MOCVD) process were presented. The performance of this device was at par to that of similar devices constructed on LT-GaAs grown by MBE. Responsivity and current-voltage measurements were carried out using a standard I-V curve tracer and a dc probing station. A contactless electro-optic sampling method and a sampling oscilloscope were employed to derive the impulse response of the detector. The selective nature of the presented growth methods was deemed a promising property for a possible in situ, maskless integration of optoelectronic devices.