Effect of solvent vapour annealing on optical properties of zno nanostructure films / Quratu'aini Abdul Aziz

In this present work the optical properties of ZnO thin film have been studied
and prepared by sol-gel spin coating process. Zinc acetate dihydrate, ethanol
and diethanolamine were used as starting materials, solvent and stabiliser.
Thin films of ZnO were prepared on glass substrate at 500°C. Its sol-gel was
spin coated for 60 second at 1000 rpm, 2000 rpm and 3000 rpm for different
spin coating speed rate and spin coated for 60 second at 1000 rpm with
various times of solvent vapour annealing which is 0 min, 10 mins, 30 mins
and 60 mins. These parameters were used to investigate the influence and
effect on the fabrication on the thin films. Optical properties have been
performed as well as determine the thin film surface thickness. Optical
characterization was analysed using the UV-VIS spectroscopy and
Photoluminescence spectroscopy. While the surface thickness was analysed
using the profilometer. All film exhibits a transmittance about > 90% along
the visible range up to 800 nm and a sharp absorption onset about 380 nm and
the optical band gap energy of the thin film is found to be around of 3.26 eV.
Intense UV photoluminescence properties is observed and showed significant
changes in the optical properties providing evidence for several types of
intrinsic defects in ZnO thin film such as oxygen vacancy (Vo), oxygenoxygen
vacancy (Vo+), zinc vacancy (Vzn), singly charge zinc vacancy
(Vzn+), antisite oxygen (OZn), antisite zinc (Zno), interstitial oxygen (Oi) and
interstitial zinc (Zni) in ZnO thin film. The thicknesses of the films decreased
with increase in coating speed and increase with the increasing in times of
solvent vapour annealing. The intense UV emission with narrow FWHM was
also obtained from the ZnO thin film.