Design of Atcd three Color Detector for Color Detection in Transient Regime

1998 ◽  
Vol 507 ◽  
Author(s):  
F. Irrera ◽  
F. Palma ◽  
F. Lemmi ◽  
M. Diotallevi

ABSTRACTIn this paper we present the characterization of an ATCD three color detector used in the charge integration regime, as necessary in large area matrices. In particular, we present linearity measurements of mesa insulated devices and characterization of the self-bias process occurring in the transient read-out of stacked structures. A new system architecture is introduced which considers interlaced row charge restore, and separates the charge restore process from the charge sampling process in order to reach self-bias within a short frame time.

2007 ◽  
Vol 556-557 ◽  
pp. 303-306 ◽  
Author(s):  
Nobuyoshi Yashiro ◽  
Kazuhiko Kusunoki ◽  
Kazuhito Kamei ◽  
Akihiro Yauchi

We carried out the characterization of the crystallinity of the solution growth self-standing silicon carbide (SiC) crystals, which were grown from Si-C-Ti ternary solution with Accelerated Crucible Rotation Technique (ACRT). The self-standing crystal exhibited homogeneous green color without cracks and inclusions. The crystallinity of the self-standing crystal was characterized by various precise XRD diffraction measurements, such as の-scan rocking curve measurement, X-ray topography and reciprocal lattice mapping. The Full Width at Half Maximum (FWHM) of the の-scan rocking curves was about 20 arcsec. The X-ray topography showed a large area with a homogeneous orientation. The reciprocal lattice mapping exhibited a sharp single peak indicating the excellent crystallinity. Finally we confirmed rather high crystallinity of the self-standing crystals by etch pits measurement using molten KOH etching.


2000 ◽  
Vol 609 ◽  
Author(s):  
D. Caputo ◽  
L. Colalongo ◽  
F. Irrera ◽  
F. Lemmi ◽  
F. Palma

ABSTRACTPractical use of amorphous silicon stacked-junction color detectors in large-area arrays requires periodic readout of the photo-charge stored in the capacitance of the device by a transient technique of sensing. In any stacked-junction devices, color information is obtained by the “self-biasing” process: during an integration time, the three junctions independently lose charge; during the readout pulse, the capacitances of the three junctions in electrical series are re-charged. Equilibrium is reached after a few cycles, when the charge integrated in a cycle by each junction is the same, and equals the readout charge. The amount of charge is determined by the reverse biased junction and accounts for the light intensity.Dimensioning the amorphous silicon Thin Film Transistor (TFT) used as a pixel switch for the detector is a critical part of the project of a color imager. The actual design determines the self-bias process duration and the readout accuracy. The typical large thickness difference between the detector junctions makes the constraints for the switching process extremely demanding: since a greater capacitance is expected in the thinner top junction detecting blue radiation, the on-resistance must be reduced. Since the front junction does not ensure full rejection of green and red light, a calculation must be performed to extract the information on blue radiation. This requires further precision in the readout process.In this work we present a simulation study of the self-biasing process. Both a-Si:H TFT and the a-Si:H p-i-n-i-p two-color detectors are simulated by a finite-elements two-dimensional simulator ensuring a correct modeling of both the devices. Simulations allow to study in detail the timing and the accuracy of the self-biasing process. Including electrostatic capacitance and trapped charge, a set of design rules for the TFT is achieved in terms of on-state design. Similar considerations can be extended to the case of ATCD three-color detectors.


1996 ◽  
Vol 420 ◽  
Author(s):  
F. Irrera ◽  
F. Lemmi ◽  
F. Palma

AbstractLarge area color image scanners are currently being widely investigated. The a-Si:H/a-SiC:H Adjustable Threshold Color Detector (ATCD) recently presented by the authors is suitable for greatly simplifying the structure of the arrays since ATCDs have just two external electrical connections. This makes possible to use the row-column addressing of pixels.In this work, the transient operation of ATCDs in the charge integration regime is discussed. Charge integration is operated by photocurrent discharging the three series connected capacitances which compose the device structure. The penetration depth of the incident radiation depends on the wavelength and determines which of the three capacitances is discharged. The applied bias voltage determines the polarization of the three junctions and the three capacitance actually sensed. Correct blue, green and red light detection is shown in the read-out transients and the read-out and saturation times are presented. Finally design rules of the device and read-out system are given in order to achieve a correct detection of the three colors.


Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1736
Author(s):  
Zengchong Yang ◽  
Xiucheng Liu ◽  
Bin Wu ◽  
Ren Liu

Previous studies on Lamb wave touchscreen (LWT) were carried out based on the assumption that the unknown touch had the consistent parameters with acoustic fingerprints in the reference database. The adaptability of LWT to the variations in touch force and touch area was investigated in this study for the first time. The automatic collection of the databases of acoustic fingerprints was realized with an experimental prototype of LWT employing three pairs of transmitter–receivers. The self-adaptive updated weight coefficient of the used transmitter–receiver pairs was employed to successfully improve the accuracy of the localization model established based on a learning method. The performance of the improved method in locating single- and two-touch actions with the reference database of different parameters was carefully evaluated. The robustness of the LWT to the variation of the touch force varied with the touch area. Moreover, it was feasible to locate touch actions of large area with reference databases of small touch areas as long as the unknown touch and the reference databases met the condition of equivalent averaged stress.


Symmetry ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1432
Author(s):  
Dmitry O. Chernyshov ◽  
Andrei E. Egorov ◽  
Vladimir A. Dogiel ◽  
Alexei V. Ivlev

Recent observations of gamma rays with the Fermi Large Area Telescope (LAT) in the direction of the inner galaxy revealed a mysterious excess of GeV. Its intensity is significantly above predictions of the standard model of cosmic rays (CRs) generation and propagation with a peak in the spectrum around a few GeV. Popular interpretations of this excess are that it is due to either spherically distributed annihilating dark matter (DM) or an abnormal population of millisecond pulsars. We suggest an alternative explanation of the excess through the CR interactions with molecular clouds in the Galactic Center (GC) region. We assumed that the excess could be imitated by the emission of molecular clouds with depleted density of CRs with energies below ∼10 GeV inside. A novelty of our work is in detailed elaboration of the depletion mechanism of CRs with the mentioned energies through the “barrier” near the cloud edge formed by the self-excited MHD turbulence. This depletion of CRs inside the clouds may be a reason for the deficit of gamma rays from the Central Molecular Zone (CMZ) at energies below a few GeV. This in turn changes the ratio between various emission components at those energies and may potentially absorb the GeV excess by a simple renormalization of key components.


2015 ◽  
Vol 135 ◽  
pp. 35-42 ◽  
Author(s):  
A. Gerber ◽  
V. Huhn ◽  
T.M.H. Tran ◽  
M. Siegloch ◽  
Y. Augarten ◽  
...  

2014 ◽  
Vol 12 (40) ◽  
pp. 7932-7936 ◽  
Author(s):  
Benjamin M. Schulze ◽  
Davita L. Watkins ◽  
Jing Zhang ◽  
Ion Ghiviriga ◽  
Ronald K. Castellano

Reported is characterization of the self-assembly of π-conjugated oligomers, molecules studied recently in photovoltaic devices, using variable temperature diffusion ordered spectroscopy; the approach has allowed estimation of assembly size, shape, and molecularity.


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