Arsenic-doped GaN films were grown via metalorganic chemical vapor deposition using trimethylgallium, ammonia, and arsine precursors. The arsenic concentration increases from3×1016to5×1017 cm−3in response to a change in arsine mole fraction from3.3×102to3.2×104 ppm.The electron mobility increases with arsenic content reaching a maximum value of374 cm2/V sat 300 K. In addition, the integrated photoluminescence intensity exhibits a 35-fold increase in magnitude at 300 K. To explain these findings, a simple physical model is proposed in which arsenic “impurities” occupy otherwise vacant sites on both the gallium and nitrogen sublattices. ©1998 American Institute of Physics.