Fortunato, E., Barquinha Pereira Gonçalves Martins P. L. G. "
Multicomponent wide band gap oxide semiconductors for thin film transistors."
Proceedings of International Meeting on Information Display. Vol. 2006. 2006. 605-608.
AbstractThe recent application of wide band gap oxide semiconductors to transparent thin film transistors (TTFTs) is making a fast and growing (r)evolution on the contemporary solid-state electronics. In this paper we present some of the recent results we have obtained using wide band gap oxide semiconductors, like indium zinc oxide, produced by rf sputtering at room temperature. The devices work in the enhancement mode and exhibit excellent saturation drain currents. On-off ratios above 106 are achieved. The optical transmittance data in the visible range reveals average transmittance higher than 80%, including the glass substrate. Channel mobilities are also quite respectable, with some devices presenting values around 25 cm2/Vs, even without any annealing or other post deposition improvement processes. The high performances presented by these TTFTs associated to a high electron mobility, at least two orders of magnitude higher than that of conventional amorphous silicon TFTs and a low threshold voltage, opens new doors for applications in flexible, wearable, disposable portable electronics as well as battery-powered applications.
Fortunato, E., Gonçalves Marques Assunção Ferreira Águas Pereira Martins A. A. V. "
Gallium zinc oxide coated polymeric substrates for optoelectronic applications."
Materials Research Society Symposium - Proceedings. Vol. 769. 2003. 291-296.
AbstractHighly transparent and conductive ZnO:Ga thin films were produced by rf magnetron sputtering at room temperature on polyethylene naphthalate substrates. The films present a good electrical and optical stability, surface uniformity and a very good adhesion to the polymeric substrates. The lowest resistivity obtained was 5×10-4 Ωcm with a sheet resistance of 15 Ω/sqr and an average optical transmittance in the visible part of the spectra of 80%. It was also shown that by passivating the polymeric surface with a thin SiO2 layer, the electrical and structural properties of the films are improved nearly by a factor of 2.
Fortunato, E., Vieira Ferreira Carvalho Lavareda Martins M. L. C. "
Large area position sensitive detector based on amorphous silicon technology."
Materials Research Society Symposium Proceedings. Vol. 297. 1993. 981-986.
AbstractWe have developed a rectangular dual-axis large area Position Sensitive Detector (PSD), with 5 cm×5 cm detection area, based on PIN hydrogenated amorphous silicon (a-Si:H) technology, produced by Plasma Enhanced Chemical Vapor Deposition (PECVD). The metal contacts are located in the four edges of the detected area, two of them located on the back side of the ITO/PIN/Al structure and the others two located in the front side. The key factors of the detectors resolution and linearity are the thickness uniformity of the different layers, the geometry and the contacts location. Besides that, edge effects on the sensor's corner disturb the linearity of the detector. In this paper we present results concerning the linearity of the detector as well as its optoelectronic characteristics and the role of the i-layer thickness on the final sensor performances.
Fortunato, Elvira, Lavareda Guilherme Martins Rodrigo Soares Fernando Fernandes Luis. "
From intelligent materials to smart sensors."
Proceedings of SPIE - The International Society for Optical Engineering. Vol. 2779. 1996. 269-274.
AbstractA Linear array Thin Film Position Sensitive Detector (LTFPSD) based on hydrogenated amorphous silicon (a-Si:H) is proposed for the first time, taking advantage of the optical properties presented by a-Si:H devices we have developed a LTFPSD with 128 integrated elements able to be used in 3D inspections/measurements. Each element consists on a 1D LTFPSD, based on a p.i.n. diode produced in a conventional PECVD system, where the doped layers are coated with thin resistive layers to establish the required device equipotentials. By proper incorporation of the LTFPSD into an optical inspection camera it will be possible to acquire information about an object/surface, through the optical cross- section method. The main advantages of this system, when compared with the conventional CCDs, are the low complexity of hardware and software used and that the information can be continuously processed (analogue detection).
Fortunato, Elvira, Lavareda Guilherme Martins Rodrigo Soares Fernando Fernandes Luis. "
High-detection resolution presented by large-area thin-film position-sensitive detectors."
Proceedings of SPIE - The International Society for Optical Engineering. Vol. 2397. 1995. 259-270.
AbstractThe aim of this work is to present the main optoelectronic characteristics of large area 1D position sensitive detectors based on amorphous silicon p-i-n diodes. From that, the device resolution, response time and detectivity are derived and discussed concerning the field of applications of the 1D thin film position sensitive detectors.