Characteristics of SnO<sub>2</sub>:F Thin Films Deposited by Ultrasonic Spray Pyrolysis: Effect of Water Content in Solution and Substrate Temperature
- 1 Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20-364, México, D.F.04510, Mexico
- 2 Departamento de Ingeniería Eléctrica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional CINVESTAV-IPN, SEES, Apartado 14740, México, D.F. 07360, Mexico
- 3 Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, Puebla 72570, Mexico
- 4 Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, Puebla 72570, Mexico
- 5 Departamento de Ingeniería Eléctrica, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional CINVESTAV-IPN, SEES, Apartado 14740, México, D.F. 07360, Mexico
Abstract
Fluorine doped tin oxide, SnO 2 :F, thin films were deposited by ultrasonic chemical spray starting from tin chloride and hydrofluoric acid. The physical characteristics of the films as a function of both water content in the starting solution and substrate temperature were studied. The film structure was polycrystalline in all cases, showing that the intensity of (200) peak increased with the water content in the starting solution. The electrical resistivity decreased with the water content, reaching a minimum value, in the order of 8 × 10 -4 Ωcm, for films deposited at 450℃ from a starting solution with a water content of 10 ml per 100 ml of solution; further increase in water content increased the corresponding resistivity. Optical transmittances of SnO 2 :F films were high, in the order of 75%, and the band gap values oscillated around 3.9 eV. SEM analysis showed uniform surface morphologies with different geometries depending on the deposition conditions. Composition analysis showed a stoichiometric compound with a [Sn/O] ratio around 1:2 in all samples. The presence of F into the SnO 2 lattice was detected, within 2 at % respect to Sn.
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