Sputtered Indium Tin Oxide thin films deposited on glass substrate for photovoltaic application
DOI:
https://doi.org/10.24084/repqj08.720Abstract
Polycrystalline indium tin oxide (ITO) films were
prepared on glass substrates by radio frequency (RF) sputtering
system from a high density target (90wt. In2O3 and 10 wt.
%SnO2 ). X-ray diffraction (XRD) and Scanning Electron
Microscopy (SEM) experiments were performed to study the
structure and the surface morphology of these samples. The
results show that the as-deposited ITO thin films deposited on
glass have a <100> texture, as the film grows the preferred
orientation changes from <100> to <111>. The lattice
parameters are found to be larger than the bulk value, indicating
that the samples are under a tensile stress. The grain size
increases with increasing thickness. SEM images show a dense
granular structure with grains having different shapes and sizes.
After deposition, the samples have been annealed in air at
temperature T around 400°C for 1 hour. We found that the
<111> texture becomes stronger after the annealing treatment.
A large increase in the grain size after annealing is also
observed. The lattice constant decreases with T to become
closer to the bulk value, i.e. annealing seems to relieve the
stress present in the as-deposited films. The optical transmisión
is greater than 80 % in the visible region.The refractive index n
values are found to be in the 1.7-1.9 range. The energy gap
values are between 3.58 and 3.88 eV .