Room-temperature growth of crystalline indium tin oxide films on glass using low-energy oxygen-ion-beam assisted deposition Electrical, optical, and structural properties of indium-tin-oxide thin films deposited on polyethylene terephthalate substrates by rf sputtering Indium tin oxide ͑ITO͒ thin films, on polyethylene napthalate ͑PEN͒ of both good electrical and optical properties were obtained by radio-frequency sputtering. The optoelectronic properties of the ITO films on PEN substrate were evaluated in terms of the oxygen content and the surface morphology. Rutherford backscattering spectrometry analysis was used to determine the oxygen content in the film. Hall-effect measurements were used to evaluate the dependence of electrical properties on oxygen content. The results showed that the resistivity of the ITO film increases with increasing oxygen content. For an oxygen content of 1.6ϫ 10 18 -2.48ϫ 10 18 atoms/ cm 2 , the resistivity varied from 0.38ϫ 10 −2 to 1.86ϫ 10 −2 ⍀ cm. Typical resistivities were about ϳ10 −3 ⍀ cm. UV-Vis spectroscopy and atomic force microscopy measurements were used to determine the optical transmittance and surface roughness of ITO films, respectively. Optical transmittances of ϳ85% were obtained for the ITO thin films. Our results revealed that substrate roughness were translated onto the deposited ITO thin layers. The ITO surface roughness influences both the optical and electrical properties of the thin films. For a 125 m PEN substrate the roughness is 8.4 nm, whereas it is 3.2 nm for 200 m substrate thicknesses. The optical band gap is about 3.15 eV for all ITO film and is influenced by the polymer substrate. A model is proposed that the optical transmittance in the visible region is governed by the carrier concentration in the ITO thin films.