We report the use of Te as an n-type dopant in GaAs core−shell p-n junction nanowires for use in photovoltaic devices. Te produced significant change in the morphology of GaAs nanowires grown by the vapor−liquid−solid process in a molecular beam epitaxy system. The increase in radial growth of nanowires due to the surfactant effect of Te had a significant impact on the operating characteristics of photovoltaic devices. A decrease in solar cell efficiency occurred when the Te-doped GaAs growth duration was increased.