To assess the suitability of alternative arsenic compounds for device applications, development of growth procedures for controlled n and p doping are required. In this paper we report the first studies of the doping characteristics of sulfur, silicon, and carbon species in GaAs films grown with tertiarybutylarsine, t-BuAsH2. Hydrogen sulfide, H2S, and hexamethyldisilane, (CH3)6Si2, were used as dopant sources. The effects of growth temperature, dopant source concentration, V/III ratio and substrate crystallographic orientation on dopant incorporation were investigated. We demonstrate the capability of controllably doping GaAs films grown with t-BuAsH2, and report the first fabrication of active devices (n+-n metal-semiconductor field effect transistors) from t-BuAsH2-grown material. These devices exhibited dc and microwave performance comparable to that achieved with arsine-grown devices.