  SnO2 nanoparticles with different percentage of Al (5%, 15%, and25%) were
synthesized by sol-gel method. The structure and nature of nanoparticles are
determined by of X-ray diffraction analysis. Also morphology of the samples is
evaluated by SEM. Moreover, the optical properties of the samples are
investigated with UV-Visible and FT-IR. The XRD patterns are indicated that all
samples and incorporation aluminum ions into the SnO2 lattice have tetragonal
rutile structure. The crystalline size of nanoparticles is decreased with
increasing the Al percentage. The SEM results confirmed that the size of
nanoparticles decreases with increasing the Al percentage. Also, FT-IR and
UV-Visible results showed that the optical band gap of nanoparticles increases
with the increasing the Al percentage. Finally, we have used the EDX analysis
to study the chemical composition of the products. Pure tin and oxygen have
been observed. The doped samples showed the existence of Al atoms in the
samples of the crystal structure of SnO2.
