Abstract

In this research, SnO2 films were prepared by
atmospheric pressure chemical vapor deposition technique
on a glass substrate. Then, the effects of oxygen and
nitrogen flow rates and deposition time on the structural,
optical and electrical properties of the thin films were
studied. The films were characterized by X-ray diffraction
(XRD), field emission scanning electron microscopy,
atomic force microscopy, electrical resistance measurements
using two-point probe technique, Hall Effect, photoconductivity
effect and optical absorption (UV–Vis). The
films had uniform polycrystalline structure. The average
optical band gap of the films was 3.8 eV. The results of
Hall Effect showed that majority carriers were n-type and
carrier concentration varies in the range of 5.84 9 1018–
1.89 9 1019 cm-3. Increasing oxygen flow rate led to
increasing the specific resistance, photosensitivity and
Seebeck coefficient (at 350 K), and also decreasing optical
band gap, mean grain size and surface roughness plus
higher XRD peaks. Increasing nitrogen flow rate led to
decreasing optical band gap, specific resistance, and photosensitivity
and Seebeck coefficient (at 350 K). Increasing
the deposition time led to an increase–decrease trend in the
optical band gap, a decrease–increase trend in specific
resistance and an increase in photosensitivity and Seebeck
coefficient (at 350 K). The average transmittance and
optical band gap of films were 82 % and 3.8 eV, respectively.
Hall Effect studies revealed that the films exhibit
n-type conductivity.