Correia, A.a b, Martins Fortunato Barquinha Goes R. a E. a. "
Design of a robust general-purpose low-offset comparator based on IGZO thin-film transistors."
Proceedings - IEEE International Symposium on Circuits and Systems. Vol. 2015-July. 2015. 261-264.
AbstractThis paper presents a low-offset comparator based on n-type amorphous indium gallium zinc oxide thin-film transistors (TFTs). An a-Si:H TFT model was adapted to fit the electrical characterization data obtained for these devices. The proposed comparator comprises three pre-amplification stages, a positive-feedback analog latch and a fully dynamic digital latch. Simulation results show that the proposed circuit can work at several tens of kHz, with an accuracy of the order of 10 mV, considering a supply voltage of 10 V and a current consumption of 380 μA. Monte-Carlo simulations exhibit a 1-sigma random offset voltage smaller than 10 mV and 40 mV, respectively, with and without using autozeroing techniques. © 2015 IEEE.
Martins, R., Lavareda Soares Fortunato G. F. E. "
Detection limit of large area 1D thin film position sensitive detectors based in a-Si:H P.I.N. diodes."
Materials Research Society Symposium - Proceedings. Vol. 377. 1995. 791-796.
AbstractThe aim of this work is to provide the basis for the interpretation of the steady state lateral photoeffect observed in p-i-n a-Si:H 1D Thin Film Position Sensitive Detectors (1D TFPSD). The experimental data recorded in 1D TFPSD devices with different performances are compared with the predicted curves and the obtained correlation's discussed.
Martins, R.a, Costa Águas Soares Marques Ferreira Borges Fortunato D. a H. a. "
Detection limits of a nip a-Si:H linear array position sensitive detector."
Materials Research Society Symposium Proceedings. Vol. 808. 2004. 507-512.
AbstractThis paper presents results of the spatial and frequency detection limits of an integrated array of 32 one-dimensional amorphous silicon thin film position sensitive detectors with a nip structure, under continuous and pulsed laser operation conditions. The data obtained show that 0.45×0.06 cm arrays, occupying a total active area of about 1 cm2 have a spatial resolution better than 10 μm (modulation transfer function of about 0.2), with a cut-off frequency of about 6.8 KHz. Besides that, under pulsed laser conditions the device non-linearity has its minimum (about 1.6%), for a frequency of about 200Hz. Up to the limits of the cut-off frequency, the device non-linearity increases to values above 4%.
Zhang, S.a b, Liao Xu Martins Fortunato Kong X. a Y. a. "
The diphasic nc-Si/a-Si:H thin film with improved medium-range order."
Journal of Non-Crystalline Solids. 338-340 (2004): 188-191.
AbstractA series of silicon film samples were prepared by plasma enhanced chemical vapor deposition (PECVD) near the threshold from amorphous to nanocrystalline state by adjusting the plasma parameters and properly increasing the reactions between the hydrogen plasma and the growing surface. The microstucture of the films was studied by micro-Raman and Fourier transform infrared (FTIR) spectroscopy. The influences of the hydrogen dilution ratio of silane (R H = [H2]/[SiH4]) and the substrate temperature (Ts) on the microstructural and photoelectronic properties of silicon films were investigated in detail. With the increase of RH from 10 to 100, a notable improvement in the medium-range order (MRO) of the films was observed, and then the phase transition from amorphous to nanocrystalline phase occurred, which lead to the formation of diatomic hydrogen complex, H 2 * and their congeries. With the increase of T s from 150 to 275 °C, both the short-range order and the medium range order of the silicon films are obviously improved. The photoconductivity spectra and the light induced changes of the films show that the diphasic nc-Si/a-Si:H films with fine medium-range order present a broader light spectral response range in the longer wavelength and a lower degradation upon illumination than conventional a-Si:H films. © 2004 Elsevier B.V. All rights reserved.