Optical Properties of Zinc Oxide Thin Films

Abstract

The aim of this study to investigate the influence of annealing of

temperatures and the effect of laser radiation on the optical

transmittance and absorbance of ZnO thin films. In this study

evaporation, casting and coating methods were used for preparation and

deposition of ZnO on glass substrate . The materials ZnCL

2

, NaOH

and NH

3

as completing agents were used for preparation of ZnO thin

films at room temperature. The weighting and micro office picture

manager methods are used for thickness measured. The UV

spectrophotometer in range 190 nm are to 1100 nm to investigate

samples ZnO thin film before and after treatment. The transmittance

of ZnO thin films samples is found before annealing to approximately

between zero and 2.34 % at 296 nm≤ λ≤ 302 nm at throughout UV –

VIS regions . Also the film show that the optical absorbance high in

UV region then decay exponentially with increasing the wavelength .

After annealing temperature, it was noticed that the optical

transmittance increased linearly with increasing temperature . The film

high transmittance value 69% in wavelength 400 nm at 550 ̊C with

lower thickness (0.009 μm) . And the film is lower transmittance value

approximately 0% in wavelength 301 nm at lower temperature 450 ̊C.

Also the film show increase of the optical absorbance with decrease of

temperature where the beak value in UV region at wavelength 301nm at

450 ̊C with higher thickness , then decreasing with increasing

wavelength to reach lower value approximately at wavelength 316nm at

higher temperature 550 ̊C . Other samples at constant temperatures in

500 ̊C show the film high transmittance approximately (1.97%) in UV

region at wavelength 292 nm at 500 ̊C, and the film show peak

absorbance in UV region at wavelength 301 nm then decreasing with

2

increasing wavelength throughout UV-VIS-NIR regions at 500 ̊C .

Finally some samples annealed with laser radiation at 20 minutes .

These samples show the increasing of transmittance and decreasing of

absorbance after annealing with laser radiation throughout UV-VIS-

NIR regions . Also we notice increasing of transmittance and

decreasing of absorbance with laser radiation at 20 minutes exposured