Regensburg 2007 – scientific programme
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DS: Fachverband Dünne Schichten
DS 4: Nanoengineered Thin Films
DS 4.2: Talk
Monday, March 26, 2007, 11:30–11:45, H34
Tuning the structure of electrodeposited ZnO — •Thomas Loewenstein1, Christian Neumann2, Joachim Sann2, Bruno K. Meyer2, and Derck Schlettwein1 — 1Institut für Angewandte Physik, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany — 2I. Physikalisches Institut, Justus-Liebig-Universität Gießen, 35392 Gießen, Germany
Zinc oxide thin films were electrodeposited on (0001) GaN and (0001) ZnO from aqueous electrolytes. Electrochemical deposition of compound semiconductors is attractive because of a widely tuneable nanostructure, especially if molecular adsorbates serve as structure directing agents as shown in this study for ZnO/Eosin Y hybrid materials. Scanning electron microscopy (SEM) revealed the formation of domains with different crystal sizes pointing at a varying density of nucleation sites on the substrate. Crystalline ZnO was deposited as proven by X-ray diffraction (XRD). The intensity pattern showed the expected preferential orientation with the c- plane of ZnO parallel to GaN (0001). XRD rocking curves with FWHM = 0.25∘ indicated a surprisingly high level of in-plane orientation of the grown ZnO crystalline domains. The peak position of (0002) ZnO was shifted by 2Θ = 1.3∘. This difference and the corresponding simultaneous shift of (0004) ZnO were explained by a lattice expansion by 3.6 % in the c-direction. This clearly indicated the strong influence of the Eosin Y molecules adsorbed during the growth of ZnO and implications for the use of electrodeposited ZnO in practical devices are discussed.