The effect of argon ion irradiation on vacuum-evaporated as-grown Sb2Te3 films in a dense plasma focused device (DPF) was studied by structural, compositional, and morphological analyses. The as-grown films consisted of both stoichiometric and nonstoichiometric Sb2Te3 phases with traces of Te. Ion energy greater than 1 MeV promoted the formation of nonstoichiometric SbxTe1-x phase and the oxidation of Sb. Ion energy less than 1 MeV promoted the formation of single stoichiometric Sb2Te3 phase and a homogeneous distribution of grain size with preferred orientation.