Structural and optical properties of (Zn,Mn)O thin films prepared by atomic layer deposition

This paper investigates manganese-doped zinc oxide (ZnMnO) thin films grown using the atomic layer deposition (ALD) technique. ZnO and MnO layers were deposited alternatively using diethyl zinc and manganese (III) acetylacetonate (Mn(acac)(3)) as metallic precursors. A suppressed growth rate for both materials was observed during the growth of ZnMnO samples, which is due to reduced adsorption of the precursor molecules on the surface of the sample. Structural characterization of the ZnMnO films shows a weak polycrystalline structure for the as-deposited thin films. On the other hand, thermally annealed samples demonstrated a textured polycrystalline structure with a distinct (002) orientation. A red shift in the near band edge absorption was observed by increasing the Mn:Zn ratio. The results of this work demonstrate the potential in ALD growth of high-quality wide bandgap ZnMnO thin films that can be used as an active semiconductor material in memory and logic devices.