Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7119252 | Materials Science in Semiconductor Processing | 2015 | 6 Pages |
Abstract
Fluorine doped tin oxide (FTO) films were fabricated on a glass substrate by a green sol-gel dip-coating process. Non-toxic SnF2 was used as fluorine source to replace toxic HF or NH4F. Effect of SnF2 content, 0-10 mol%, on structure, electrical resistivity, and optical transmittance of the films were investigated using X-ray diffraction, Hall effect measurements, and UV-vis spectra. Structural analysis revealed that the films are polycrystalline with a tetragonal crystal structure. Grain size varies from 43 to 21 nm with increasing fluorine concentration, which in fact critically impacts resultant electrical and optical properties. The 500 °C-annealed FTO film containing 6 mol% SnF2 shows the lowest electrical resistivity 7.0Ã10â4 Ω cm, carrier concentration 1.1Ã1021 cmâ3, Hall mobility 8.1 cm2Vâ1 sâ1, optical transmittance 90.1% and optical band-gap 3.91 eV. The 6 mol% SnF2 added film has the highest figure of merit 2.43Ã10â2 Ωâ1 which is four times higher than that of un-doped FTO films. Because of the promising electrical and optical properties, F-doped thin films prepared by this green process are well-suited for use in all aspects of transparent conducting oxide.
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Authors
Quang-Phu Tran, Jau-Shiung Fang, Tsung-Shune Chin,