Topic, M., Smole Furlan Fortunato Martins F. J. E. "
Examination of 1-D position sensitive detector performance through analysis of front contact heterojunction."
Materials Research Society Symposium - Proceedings. Vol. 420. 1996. 171-176.
AbstractThe influence of different TCOs (SnO2 and ITO) on the photoelectrical properties of 1-D position sensitive detectors based on p-i-n structures was studied. A strong cross-contamination in the p-layer and contamination in the i-layer reduce the quality of the device. Numerical analysis of TCO/p-i-n structure also revealed a strong increase in defect states at the p-layer surface which can be attributed to the reduction of TCO. ITO seems to be less appropriate for a front TCO, although the spectral response of the p-i-n structure under reverse bias is not significantly affected by the conditions at the TCO/p heterojunction.
Fortunate, E., Gonçalves De Carvalho Pimentel Lavareda Marques Martins A. C. N. "
Enhancement of the electrical properties of ITO deposited on polymeric substrates by using a ZnO buffer layer."
Materials Research Society Symposium Proceedings. Vol. 814. 2004. 231-236.
AbstractIn this paper we present the effect of the insertion of a non-doped nanocrystalline zinc oxide/buffer layer on the electrical, optical and structural properties of indium tin oxide produced at room temperature by radio frequency plasma enhanced reactive thermal evaporation on polymeric substrates. The electrical resistivity of the ITO films is reduced by more than two orders of magnitude (4.5×10-1 to 2.9×10-3 Ωcm). From the Hall effect measurements it is observed that the large decrease associated to the electrical resistivity, is due to the increase associated to the Hall mobility. Concerning the optical properties no effect was observed, being the transmittance in the visible and near the infra red region always higher than 80%.
Martins, R., Ferreira Carvalho Guimarães I. N. L. "
Engineering of plasma deposition systems used for producing large area a-Si:H devices."
Journal of Non-Crystalline Solids. 137-138 (1991): 757-760.
AbstractOne of the main problems in producing large area amorphous silicon devices concerns films uniformity. In this paper we present data concerning the role of reactor geometry and design and on the film performances as well as the problems related to mechanical mismatches in scaling up the reactor size. © 1991 Elsevier Science Publishers B.V. All rights reserved.
Ferreira, I., Raniero Fortunato Martins L. E. R. "
Electrical properties of amorphous and nanocrystalline hydrogenated silicon films obtained by impedance spectroscopy."
Thin Solid Films. 511-512 (2006): 390-393.
AbstractNanocrystalline hydrogenated silicon (nc-Si:H) thin films are generally accepted to be a two phase material-Si crystalline and Si:H amorphous. This work reports the use of impedance spectroscopy to determine the amorphous and crystalline electrical conductivity of a/nc-Si:H films obtained by hot wire chemical vapour deposition. Different relaxation time or time constants are detected, if the film is composed by inhomogeneous material, by measuring ac impedance in a wide range of frequencies. Relating the conduction mechanism of the film to a series of two RC circuits constituted by a resistance and a capacitor in parallel, we may determine distinct ac conductivities and correlate that to the crystalline, amorphous and interface components. The amorphous films analysed exhibit one ac conductivity component while for nanocrystalline films two ac conductivity components are observed. The average value of ac conductivities is in agreement with that of dc conductivity. © 2006.
b b b b b b b Martins, R.a b, Carvalho Fortunato Maçarico Santos Baia Viera Guimarães N. a E. a. "
Effects of U.V. light on the transport properties of a-Si : H films during their growth."
Journal of Non-Crystalline Solids. 97-98 (1987): 1399-1402.
AbstractThe influence of U.V. light on the transport properties of a-Si : H films during its growth in a r.f. double chamber system was investigated by conductivity, optical absorption, I.R. absorption, spectral photoconductivity and X-ray diffraction measurements. It was concluded that the presence of U.V. light during the deposition process controls the way how hydrogen is incorporated in the structure as well as the impurity atoms. The microcrystalline films investigated present sharp peaks in the I.R. spectra. Both boron and phosphorus doped films show conductivities higher than 10 S cm-1 and estimated crystalline sizes of the order of 80 Å. © 1987.