EFFECT OF DIFFERENT SUBSTRATES ON STRUCTURAL AND OPTICAL PROPERTIES OF ZnO THIN FILMS PREPARED BY PULSED LASER DEPOSITION (PLD

Abstract

ZnO thin films were deposited at 450°C on glass, Si(100) and Si-polycrystalline substrates by pulsed laser deposition (PLD) method. KrF excimer (248 nm, 25 ns, 5 Hz, 2 J/cm2) was used as a laser source. The effect of different substrates on structural and optical properties of ZnO thin films had been investigated. The experimental results obtained using X-ray diffraction (XRD) technique show that ZnO films grow in hexagonal Wurtzite-type structure with a dominant peak at ~34° with (002) orientation. The mean roughness deduced from atomic force microscopy (AFM) is found to be between 6.4 and 15.6 nm. The average transmittance of ZnO thin films deposited on glass substrates in the wavelength range from 400 to 800 nm is 80 ℅ with a band gap Eg=3.23 eV.