Defects in zinc-implanted and thermally annealed ZnO thin films were investigated by means of capacitance-voltage spectroscopy (C-V), thermal admittance spectroscopy (TAS), deep level transient spectroscopy (DLTS), and photoluminescence (PL) spectroscopy. The authors report on the formation of two donor states approximately 35 and 190 meV below the conduction band edge, observed by TAS and DLTS, respectively. In the PL spectra of a reference sample a peak at 3.366 eV was present, which diminished after the implantation, while a new peak at 3.364 eV was observed only in the spectrum of the implanted sample. Since only intrinsic ions were implanted, the authors consider the defects formed by the zinc implantation and annealing to be intrinsic.