Ceramics-Silikáty 56 (2) 117-121 (2012)

ZnO thin films prepared by spray-pyrolysis technique from organo-metallic precursor

L. Nádherný, Z. Sofer, D. Sedmidubský, O. Jankovský, M. Mikulics

Presented experiments utilize methanolic solution of zinc acetyl-acetonate as a precursor and sapphire (001) as a substrate for deposition of thin films of ZnO. The X-ray diffraction analysis revealed polycrystalline character of prepared films with preferential growth orientation along c-axis. The roughness of prepared films was assessed by AFM microscopy and represented by roughness root mean square (RMS) value in range of 1.8 - 433 nm. The surface morphology was mapped by scanning electron microscopy showing periodical structure with several local defects. The optical transmittance spectrum of ZnO films was measured in wavelength range of 200-1000 nm. Prepared films are transparent in visible range with sharp ultra-violet cut-off at approximately 370 nm. Raman spectroscopy confirmed wurtzite structure and the presence of compressive stress within its structure as well as the occurrence of oxygen vacancies. The four-point Van der Pauw method was used to study the transport prosperities. The resistivity of presented ZnO films was found 8 × 10^–2 Ω cm with carrier density of 1.3 × 10¹⁸ cm^–3 and electron mobility of 40 cm² V^–1 s^–1.

Keywords: Zinc oxide, Thin films, Spray-pyrolysis, Zinc acetyl-acetonate