Results 271 to 280 of about 801,069 (309)

Dark energy: current issues

Annalen der Physik, 2006
Abstract The observed recent accelerated expansion of the Universe constitutes a dramatic departure from traditional views. The mechanism behind this accelerated expansion is still mysterious and is a major challenge to present‐day cosmology.
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Geometry dependence of dark current in CCD's

IEEE Transactions on Electron Devices, 1984
This paper studies the scalability of dark current in reduced-geometry CCD's. The dependence of dark current on device geometry is measured from test CCD's with various channel widths. We found that dark current does not scale with channel width due to the peripheral leakage generated at the edges of the channel stops.
J.Y. Chen, C.R. Viswanathan
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Low dark current logarithmic pixels

48th Midwest Symposium on Circuits and Systems, 2005., 2005
The sensitivity of logarithmic pixels at low light levels is limited by the dark current that flows through the load transistor in the pixel in parallel with the photocurrent. A new layout for a logarithmic pixel is reported that significantly reduces the dark current in the pixel.
B. Choubey, S. Collins
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Dark current analysis of InSb photodiodes

Infrared Physics, 1984
Abstract We report on low dark current InSb photodiodes with mesa structures in which bulk g-r plus shunt resistance are the dominant current mechanisms up to approx. 700 mV reverse bias. Tunneling current dominates for large reverse bias, and bulk diffusion current dominates for forward bias > 15 mV.
F.K. Hopkins, J.T. Boyd
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Photoconductivity (Dark Current & Photo Current)

Photoconductive crystals have been employed in various photo-detecting devices such as charge coupled devices, photoresistors and infrared-based photonic systems. The dark and photocurrent properties of single crystals grown by the SEST, SR, or other methods were analyzed using a Keithley 485 picoammeter under a DC electric field at room temperature ...
B. Sahaya Infant Lasalle, Muthu Senthil Pandian, P. Ramasamy   +2 more
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Mechanisms of Photoreceptor Current Generation in Light and Darkness

Nature New Biology, 1971
PENN and Hagins first demonstrated a sustained “dark” voltage along the axis of rat retinal rods which results from membrane current leaving the inner segment and entering the outer segment1,2. They also found that the response to light (receptor potential) is a reduction in this “dark” voltage which does not alter its spatial distribution.
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Mismatch reduction for dark current suppression

2010 IEEE Sensors, 2010
In this paper we present a dark current suppression technique for low-light image sensor arrays fabricated in a standard CMOS process. It has been shown that reducing the reverse bias of a p-n junction minimizes the thermally generated dark current and increases the signal to noise ratio.
David Sander, Pamela Abshire
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Beam-current-induced Dark Current in Plumbicons

1972
Publisher Summary This chapter discusses beam-current-induced dark current in Plumbicons. The Plumbicon is a television pick-up tube with a lead oxide photoconductive sensor. Its high sensitivity, linear transfer characteristic, low lag, and good resolution have made it the preferred tube for broadcast color television.
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CURRENT STATUS OF MODERN DARK MATTER PROBLEM

International Journal of Modern Physics A, 2002
The basic methods of searching for dark matter candidates are discussed. The main topics of this talk are: (a) ground - based cavity experiments with searching for galactic axions; (b) searching for hadronic axion decay line into galactic and extragalactic light; (c) experimental search for solar and stellar axions; (d) basic methods of searching for ...
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Tunneling and dark currents in HgCdTe photodiodes

Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1989
The dc characteristics of front-illuminated ion-implanted n+ on bulk p-type Hg1−xCdxTe with x≊0.22, operating at 77 K, are modeled with three distinct mechanisms that dominate the dark current: In the zero- and low-bias region, diffusion current is the dominant current down to 60 K. For medium reverse bias, at 77 K, trap-assisted tunneling produces the
Y. Nemirovsky, D. Rosenfeld, R. Adar, A. Kornfeld   +3 more
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