Quantum mechanical scattering investigation of the thermionic and field induced emission components of the dark current in quantum well infrared photodetectors

Abstract

The thermionic emission and field induced emission components of the dark current in quantum well infrared photodetectors are investigated using a quantum mechanical scattering theory approach. Calculations are performed for an experimentally reported device. Using this as a standard, the device dimensions were altered in order to increase its detection wavelength to cover the mid-͑MIR͒ and far-infrared ͑FIR͒ regions of the spectrum. The behavior of the scattering mechanisms that contribute to the thermionic emission and field induced emission components were studied. The results highlight the change in the dominating scattering mediator across the MIR and FIR bands.

Recovery from central nervous system oxygen toxicity in the rat at oxygen pressures between 100 and 300 kPa

“…The present Wndings support our previous suggestion that recovery from CNS oxygen toxicity takes place at a PO 2 below 130 kPa (Arieli 2003;Arieli et al 2002). It has been proven that recovery from CNS oxygen toxicity can take place at levels of hyperoxia where the risk of other forms of oxygen toxicity increases (Clark and Thom 2003).…”

“…If we succeeded in establishing that recovery takes place at a PO 2 between 100 and 130 kPa, we would then continue to raise the PO 2 during the interim period in a search for the uppermost level at which recovery can occur. Experimental support for our assumption would reinforce our previous suggestion (Arieli 2003;Arieli et al 2002) that if a closedcircuit oxygen diver remains for a time at a depth less than 3 msw after having spent a period at a greater depth, his CNS oxygen toxicity index will go down and recovery from the process that leads to CNS oxygen toxicity will take place.…”

“…The risk of central nervous system (CNS) oxygen toxicity has become a prominent issue with the increased use of HBO therapy and the expansion of diving techniques to include oxygen-enriched breathing mixtures. We proposed an algorithm to calculate the risk of CNS oxygen toxicity while diving with a closed-circuit oxygen rebreather (Arieli 2003;Arieli et al 2002). This algorithm enables the calculation of a cumulative index for CNS oxygen toxicity, where the risk of CNS oxygen toxicity is related to the magnitude of the index.…”

On the coherence/incoherence of electron transport in semiconductor heterostructure optoelectronic devices

“…From a theoretical viewpoint this is more complicated than QCLs since the transitions occur from two-dimensional confined states in the quantum wells to three-dimensional extended states in the continuum, which would make the description a mixture of two-and three-dimensional states giving complications for the calculation of scattering rates. This is overcome theoretically by 'discretising the continuum' and summing all scattering rate contributions to the transport over more and more closely spaced continuum levels until convergence is acheived [44], see Fig. 7(a).…”

Physical model of quantum-well infrared photodetectors

“…Moreover, large, highly uniform QWIP focal plane arrays have been reported with a wide range of possible applications [9,10]. However, despite the extensive amount of experimental and theoretical efforts, not much work has been done on a microscopic quantum description of the processes that govern both vertical and parallel electron transport in periodic quantum structures, involving bound-bound and bound-continuum intersubband transitions [6,[11][12][13]. In order to ensure further improvement of the QWIP technology, primarily by using novel structures and material systems, a thorough understanding of fundamental physical procesess in QWIPs, as well as a first principles simulation tool are neccesary.…”