Effect of potassium and erbium co-doping on the structural, electronic, optical and magnetic properties of zinc oxide

Electronic and optical properties of (K, Er) co-doped ZnO were investigated by using FP-LAPW method with LSDA and LSDA + mBJ approximations. The lattice parameter of undoped ZnO was found in a good agreement with the experimental work; it was increased by doping ZnO with K and Er impurities. In this work, we showed the p-type doping ZnO from the band structure and density of states calculations. The band gap of ZnO was found to be decreased by co-doping with K and Er elements. We presented also the optical properties such as, the real and imaginary part of dielectric function, the refractive index and the absorption coefficient. This p-type appears by K and Er co-doping which occurs much shallow above the Fermi level. Er co-doping leads to the formation of magnetism in ZnO:K. ZnO has an absorption peak in UV region. Hence, (K, Er) co-doping leads to an optical peak in infrared region (IR) at about 1.75 eV (equivalent to 775 nm). The peak was found experimentally, and may improve the optical properties of ZnO-based devices.