Nunes, P., Fortunato Martins E. R. "
Thin film combustible gas sensors based on zinc oxide."
Materials Research Society Symposium - Proceedings. Vol. 666. 2001. F521-F526.
AbstractSensitivity tests to reductive gases such as methane, hydrogen and ethane were performed on zinc oxide (ZnO) thin films. The highest value of sensitivity was obtained for the film with a high electrical resistivity and a low thickness. The variation of the operating temperature of the film leads to a significant change in the sensitivity of the sensor with an ideal operating temperature dependence of the gas used. The sensitivity of the ZnO thin films changes linear with the increase of the gas concentration. However these films seem to be more appropriated for the detection of hydrogen following by methane and than for ethane since the value of sensitivity obtained are higher and its variation with the gas concentration more pronounced.
Fortunato, E.a, Nunes Marques Costa Águas Ferreira Costa Martins P. a A. a. "
Thin film metal oxide semiconductors deposited on polymeric substrates."
Materials Research Society Symposium Proceedings. Vol. 685. 2001. 146-151.
AbstractHighly textured transparent conducting ZnO:Al thin films have been prepared by r.f. magnetron sputtering. The films were deposited on polyester (Mylar type D, 100 μm thickness) and glass substrates at room temperature. Surface stylus profiling, X-ray diffraction, scanning electron microscopy, transmission electron microscope and Hall effect measurements as a function of temperature, using the van der Pauw technique have characterized the films. The samples are polycrystalline with a hexagonal wurtzite structure and a strong crystallographic c-axis orientation (002) perpendicular to the substrate surface (columnar structure). The ZnO:Al thin films with a resistivity as low as 3.6×10-2 Ωcm have been obtained, as deposited. © 2001 Materials Research Society.
Fortunato, E., Nunes Marques Costa Águas Ferreira Costa Martins P. A. D. "
Thin film metal oxide semiconductors deposited on polymeric substrates."
Materials Research Society Symposium - Proceedings. Vol. 666. 2001. F1131-F1136.
AbstractHighly textured transparent conducting ZnO:Al thin films have been prepared by r.f. magnetron sputtering. The films were deposited on polyester (Mylar type D, 100 μm thickness) and glass substrates at room temperature. Surface stylus profiling, X-ray diffraction, scanning electron microscopy, transmission electron microscope and Hall effect measurements as a function of temperature have been used to characterize the produced films. The samples are polycrystalline with a hexagonal wurtzke structure and a strong crystallographic c-axis orientation (002) perpendicular to the substrate surface (columnar structure). The ZnO:Al thin films with a resistivity as low 3.6×10-2 Ωcm have been obtained, as deposited.
Fortunato, E., Malik Martins A. R. "
Thin oxide interface layers in a-Si:H MIS structures."
Journal of Non-Crystalline Solids. 227-230 (1998): 1230-1234.
AbstractPd-metal/insulator/semiconductor based on hydrogenated amorphous silicon were produced by plasma enhanced chemical vapour deposition with two different oxidised surfaces: thermal in ambient air and chemical with hydrogen peroxide. The diode characteristics have been investigated using dark and light current as f(v) measurements in the temperature range from 300 K to 380 K, from which it was possible to infer the electron barrier height. The data obtained show that the incorporation of a thin insulator layer between the semiconductor and the metal improves the performances of the devices by preventing the formation of suicides at the interface. Apart from that we also show that the MIS structures with the thermal oxide presents 'better' performances than the ones with the chemical oxide due to the type of interface states and of the oxide charges associated with the interface between the insulator and the semiconductor. © 1998 Elsevier Science B.V. All rights reserved.
Barquinha, P., Martins Pereira Fortunato R. L. E. Transparent Oxide Electronics: From Materials to Devices. Transparent Oxide Electronics: From Materials to Devices., 2012.
AbstractTransparent electronics is emerging as one of the most promising technologies for the next generation of electronic products, away from the traditional silicon technology. It is essential for touch display panels, solar cells, LEDs and antistatic coatings. The book describes the concept of transparent electronics, passive and active oxide semiconductors, multicomponent dielectrics and their importance for a new era of novel electronic materials and products. This is followed by a short history of transistors, and how oxides have revolutionized this field. It concludes with a glance at low-cost, disposable and lightweight devices for the next generation of ergonomic and functional discrete devices. Chapters cover: Properties and applications of n-type oxide semiconductors P-type conductors and semiconductors, including copper oxide and tin monoxide Low-temperature processed dielectrics n and p-type thin film transistors (TFTs) - structure, physics and brief history Paper electronics - Paper transistors, paper memories and paper batteries Applications of oxide TFTs - transparent circuits, active matrices for displays and biosensors Written by a team of renowned world experts, Transparent Oxide Electronics: From Materials to Devices gives an overview of the world of transparent electronics, and showcases groundbreaking work on paper transistors. © 2012 John Wiley & Sons, Ltd.
Fortunato, E.a, Nunes Marques Costa Águas Ferreira Costa Godinho Almeida Borges Martins P. a A. a. "
Transparent, conductive ZnO:Al thin film deposited on polymer substrates by RF magnetron sputtering."
Surface and Coatings Technology. 151-152 (2002): 247-251.
AbstractIn this paper, we present the optical, electrical, structural and mechanical properties exhibited by aluminum-doped zinc oxide (ZnO:Al) thin films produced by RF magnetron sputtering on polymeric substrates (polyethylene terephthalate, PET; Mylar type D from Dupont®) with a standard thickness of 100 μm. The influence of the uniaxial tensile strain on the electrical resistance of these films was evaluated in situ for the first time during tensile elongation. In addition, the role of the thickness on the mechanical behavior of the films was also evaluated. The preliminary results reveal that the increase in electrical resistance is related to the number of cracks, as well as the crack width, which also depends on the film thickness. © 2002 Elsevier Science B.V. All rights reserved.