Physical properties of SnO2 thin films prepared by isothermal oxidation of vacuum evaporated Sn

Abstract

In this work, SnO2 thin films were prepared by thermal oxidation of Sn under oxygen atmosphere. The Sn thin films of 100 nm thickness were deposited onto Si (111) substrates by vacuum evaporation. The oxide films physical properties were investigated as a function of the annealing time. From X-ray diffraction patterns, the obtained films were SnO2 with a preferential orientation along the (101) planes. The SnO2 grain size increased as a function of the annealing time. The crystalline fraction, determined from Fourier transform infrared spectra, correlated with the grain size. From the UV–visible reflectance spectra analysis, the presence of tree layers was evidenced on the basis of Rutherford backscattering spectroscopy analysis. The SnO2 films band gap energy decreased, from 3.94 to 3.68 eV caused by the increase of the charge carrier’s density due to the grains size increase. The films thickness increases, as a function of the annealing time while the electrical resistivity decreased from 0.23 to 5.3 × 10−3 Ω cm.