There are wide uses of tin oxide thin films, especially in the field of
transparent conductors, solar cells, gas sensors and piezoelectric materials.
Laser deposition is considered one of the most important techniques followed to
obtain these film
s. In this research, we develop a technique to obtain
homogeneous thin films of tin oxide depending on vaporization of pile targets of
this oxide by continuous CO2 laser in the atmosphere, with a fan which
guarantees obtaining homogenous films. Some of these films were annealed in
different conditions. The optical microscope images revealed the presence of
high degree of homogeneity, while the X-Ray study showed different
crystallization grain orientations which depend on the preparation conditions.
The preferred direction is (110). The optical absorption gives information
about the value of the effective band gal for the samples before and after
thermal annealing. We have found that some films have Eg = 3.2 ev. before
annealing, and after long annealing they have Eg=1.3ev. In addition, the hard
annealed thin films reveal anisotropy in the optical and electrical.
Characteristics, they have different absorption coefficients in two
perpendicular directions, also there is an electrical resistance anisotropy along
these two directions especially after hard annealing. The Eb was 0.73 ev before
annealing, it became 0.37 ev for one direction and 0.32 ev for the other
direction.
