Electrical properties of ZnO films implanted with rare earth and their relationship with structural and optical parameters

Abstract

ZnO implanted with Rare Earth (RE) ions has a potential application as phosphor or in white light sources. The paper discusses the structural, optical and electrical changes caused by Yb, Dy and Pr ions implanted into thin ZnO films grown by Atomic Layer Deposition (ALD). Using channeling Rutherford Backscattering Spectrometry (RBS/c), room temperature photoluminescence (RT PL) technique and Hall effect measurements, it has been shown that the initial damages of the ZnO crystal lattice caused by the rare earth (RE) ion implantation can to a certain extent be removed via post-implantation thermal treatment, provided the fluence is lower than 1.5 × 1015 at.cm−2.A comparison of the structural optical and electrical properties of annealed ALD–ZnO:RE layers with the results of analogous studies performed on thermally untreated RE-implanted films allows us to conclude that properly selected annealing steps allow for a substantial improvement in the conductivity of the layers as well as the intensity of luminescence, which can be attributed to the appearing recrystallization phenomena in the ZnO lattice.