SnO(2) Films Deposited by Ultrasonic Spray Pyrolysis: Influence of Al Incorporation on the Properties

Aluminum-doped tin oxide (SnO [Formula: see text]:Al) thin films were produced by an ultrasonic spray pyrolysis method. The effect of aluminum doping on structural, optical, and electrical properties of tin oxide thin films synthesized at 420 [Formula: see text] C was investigated. Al doping induced a change in the morphology of tin oxide films and yielded films with smaller grain size. SnO [Formula: see text] thin films undergo a structural reordering and have a texture transition from (301) to (101), and then to (002) preferred cristallographic orientation upon Al doping. The lattice parameters (a and c) decreases with Al doping, following in a first approximation Vegard’s law. The optical transmission does not change in the visible region with an average transmittance value of 72–81%. Conversely, in the near infrared (NIR) region, the plasmon frequency shifts towards the IR region upon increasing Al concentration in the grown films. Nominally undoped SnO [Formula: see text] have a conductivity of ∼1120 S/cm, which is at least two orders of magnitude larger than what is reported in literature. This higher conductivity is attributed to the Cl [Formula: see text] ions in the SnCl [Formula: see text] ·5(H [Formula: see text] O) precursor, which would act as donor dopants. The introduction of Al into the SnO [Formula: see text] lattice showed a decrease of the electrical conductivity of SnO [Formula: see text] due to compensating hole generation. These findings will be useful for further studied tackling the tailoring of the properties of highly demanded fluorine doped tin oxide (FTO) films.