Structural, optical and half-metallic properties of Mn and As co-implanted ZnO thin films

It is found that ZnO has half-metallic properties by using Mn atoms instead of Zn atoms in ZnO. • ZnO films on the sapphire substrate were prepared by molecular beam epitaxy. • Mn ions and As ions were injected into ZnO films by ion implantation. • The absorption edges of the films were blue-shifted as the ion concentration increased. • The half-metallic properties of Mn ion implanted ZnO thin films were verified by first principles calculations. • Refractive index and extinction coefficient of ZnO films were explored by spectroscopic ellipsometry. In this work, we use ion implantation to implant Mn ions and As ions into the ZnO films prepared by molecular beam epitaxy. The surface morphology and crystalline structure of ZnO thin films are investigated by X-ray diffraction, atomic force microscopy and Raman spectroscopy. First-principles calculations discover the half-metallic property of the ZnO films implanted with Mn ions. The effects of Mn ions and As ions implantation on the absorption edges, refractive index (n), extinction coefficient (k) and dielectric constant of ZnO films are studied by transmission spectra, absorption spectroscopy and spectroscopic ellipsometric technique. From the spectroscopic ellipsometry (SE), the n and k of the films have increased after ion implantation. Due to the half-metallic properties of the Mn-implanted ZnO film, the variation trend of the peaks of n and k with wavelength is much gentler than the peak of unimplanted ZnO film. The dielectric constant measured by SE and the results of photoluminescence spectra reveal that the electron transition of ZnO films is weakened by Mn ions implantation. The results provide a new direction for the design and optimization of optoelectronic devices based on ZnO thin films with semi-metallic properties.