The dopant and compound forming behavior of As and Au impurities in Ga2Te3 is investigated by the combined application of Mössbauer spectroscopy, x-ray diffraction, optical transmission, and electrical measurements. Arsenic is shown to act as a n-type dopant in Ga2Te3, and a ternary semiconductor AuGa2Te3 is identified. The results allow for a concise description of the ohmic contact formation mechanism in alloyed Au/Te/Au/GaAs and related structures.