Effect of annealing on the physicochemical and optical properties of the APCVD titanium dioxide thin films for photovoltaic applications
DOI:
https://doi.org/10.24084/repqj09.678Abstract
In this paper, we studied the influence of thermal
annealing on the phase transformation and crystalline structure
of the APCVD titanium dioxide thin films, which in turn
influence the physicochemical properties and the optical
properties of the produced coatings, by means of standard
characterization techniques of Fourier Transform Infrared
(FTIR) Spectroscopy combined with UV-Vis Reflectance
Spectrophotometry. The absorption peaks at 423 cm-1 and 610
cm -1 which increase in intensity with the rise of annealing
temperature, were observed for the produced rutile TiO2 thin
films, by FTIR measurements. The absorption peak at 739 cm-1
due to the vibration of the Ti-O bonds, was also detected for
different annealing temperatures. From UV-Vis Reflectance
spectra measurements, the minimum average reflectance of 8.6
% was achieved on the as-deposited TiO2 thin film having an
optical band gap of 3.29 eV. The optical band gap of the
produced anatase TiO2 thin film was found to decrease from
3.25 eV to 3.20 eV when the annealing temperature increases
from 400°C to 500°C. However, it was estimated to be 3.05 eV
for the rutile TiO2 film, in good agreement with the FTIR
measurements.