Fortunato, E., Pimentel Pereira Gonçalves Lavareda Águas Ferreira Carvalho Martins A. L. A. "
High field-effect mobility zinc oxide thin film transistors produced at room temperature."
Journal of Non-Crystalline Solids. 338-340 (2004): 806-809.
AbstractIn this paper we present the first results of thin film transistors produced completely at room temperature using ZnO as the active channel and silicon oxynitride as the gate dielectric. The ZnO-based thin film transistors (ZnO-TFT) present an average optical transmission (including the glass substrate) of 84% in the visible part of the spectrum. The ZnO-TFT operates in the enhancement mode with a threshold voltage of 1.8 V. A field effect mobility of 70 cm2/Vs, a gate voltage swing of 0.68 V/decade and an on-off ratio of 5×105 were obtained. The combination of transparency, high field-effect mobility and room temperature processing makes the ZnO-TFT very promising for the next generation of invisible and flexible electronics. © 2004 Elsevier B.V. All rights reserved.
Fortunato, E.a, Assunção Gonçalves Marques Águas Pereira Ferreira Vilarinho Martins V. a A. a. "
High quality conductive gallium-doped zinc oxide films deposited at room temperature."
Thin Solid Films. 451-452 (2004): 443-447.
AbstractTransparent and highly conducting gallium-doped zinc oxide films were successfully deposited by rf sputtering at room temperature. The lowest resistivity achieved was 2.6×10-4 Ω cm for a thickness of 1100 nm (sheet resistance ≈1.6 Ω/sq), with a Hall mobility of 18 cm2/Vs and a carrier concentration of 1.3×1021 cm-3. The films are polycrystalline with a hexagonal structure and a strongly preferred orientation along the c-axis. A linear dependence between the mobility and the crystallite size was obtained. The films present a transmittance in the visible spectra between 80 and 90% and a refractive index of approximately 2, which is very close to the value reported for bulk material. © 2003 Elsevier B.V. All rights reserved.
Fortunato, E., Nunes Marques Costa Águas Ferreira Costa Martins P. A. D. "
Highly conductive/transparent ZnO:Al thin films deposited at room temperature by rf magnetron sputtering."
Key Engineering Materials. 230-232 (2002): 571-574.
AbstractTransparent conducting ZnO:Al thin films have been deposited on polyester (Mylar type D, 100 μm thickness) substrates at room temperature by r.f. magnetron sputtering. The structural, optical and electrical properties of the deposited films have been studied. The samples are polycrystalline with a hexagonal wurtzite structure and a strong crystallographic c-axis orientation (002) perpendicular to the substrate surface. As deposited ZnO:Al thin films have an 85% transmittance in the visible and infra-red region and a resistivity as low as 3.6×10-2 Ωcm. The obtained results are comparable to those ones obtained on glass substrates, opening a new field for low cost, light weight, small volume, flexible and unbreakable large area optoelectronic devices.