Structural and optical properties of zinc oxide thin films prepared by spray pyrolysis method
JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS, cilt.8, sa.1, ss.299-303, 2006 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 8 Sayı: 1
- Basım Tarihi: 2006
- Dergi Adı: JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Sayfa Sayıları: ss.299-303
- Anahtar Kelimeler: ZnO, optical properties, thin films, spray pyrolysis, EXAFS, TRANSPARENT CONDUCTING ZNO, SOLAR-CELLS, DEPOSITION, GROWTH, AL
- Çukurova Üniversitesi Adresli: Evet
Özet
Polycrystalline ZnO thin films were deposited on a glass substrate by a spray pyrolysis technique using solution of zinc acetate and air as the carrier gas at 400 degrees C temperature. Optical constants such as refractive index n and extinction coefficient k, were determined from transmittance spectrum in the ultraviolet-visible-near infrared (UV-VIS-NIR) regions using envelope methods. The films were found to exhibit high transmittance (> 90 %), low absorbance and low reflectance in the visible regions. Absorption coefficient a, and the thickness of the film t were calculated from interference of transmittance spectra. The energy band gap, and the thickness of the films were evaluated as 3.27 eV and 0.31-0.52 Pm respectively. The crystallographic structure of these films was analyzed with x-ray diffractometer. The films were polycrystalline in nature with preferred (002) orientation perpendicular to substrate surface and the grain size estimated to be 40 nm. The extended x-ray absorption fine structure (EXAFS) calculations above the K-edge of Zn in the ZnO thin film have been performed by using real-space multiple scattering of photoelectrons. For ZnO thin films, the values of the correlated mean square relative displacements of nearest-neighbor atoms derived from EXAFS spectra show good agreement with those measured from the x-ray diffraction experiments.