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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 21:15 |
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Conference: Bucharest University Faculty of Physics 2006 Meeting
Section: Electricity and Biophysics
Title:
Electrical and Optical Properties of Nanostructured ZnO Thin Films
Authors:
C. Tazlaoanu (1), L. Ion (1), G. Socol (2), I. N. Mihailescu (2), Marcela Socol (3), Larisa Magherusan (1), Felicia Ionescu (3), S. Antohe (1)
Affiliation:
(1) University of Bucharest, Faculty of Physics, Romania
(2)National Institute for Plasma Physics, and Radiation, Bucharest, Romania
c National Institute for Materials Physics, Bucharest, Romania
E-mail
santohe@solid.fizica.unibuc.ro
Keywords:
Zinc oxide, electrical properties and measurements, optical properties
Abstract:
Here we report on the results of structural, electrical and optical characterizations of nanostructured ZnO thin films. The nanostructured ZnO thin films are prepared by Pulsed Laser Deposition (PLD), which is known to be a versatile technique for deposition of solid thin films with specific structural and morphological characteristics. The films were deposited onto commercially available Indium Tin Oxide (ITO) substrates at various substrate temperatures and oxygen pressures ranging from 1.3 to 13 Pa, and were optimized for use in hybrid organic/inorganic photovoltaic cells. XRD spectra revealed they had a polycrystalline structure of wurtzite type (001), preferentially oriented in the direction of growth. On increasing substrate temperature (Ts>300° C), texture got more pronounced, and surface roughness, investigated with an atomic force microscope, was seen to decrease.The electrical properties of the films were studied in a 30 K-300 K temperature range using a closed cycle He cryostat. Electrical resistance, measured with Van der Pauw technique, was thermally activated. Charge transport occurred through either the conduction band mechanism, at high temperatures, or hopping at temperatures below 60 K. The main defects that influenced the electrical properties of the films were investigated by the method of thermally stimulated currents, and their parameters were determined. Optical characterization was conducted using absorption and reflectivity spectra.
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