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Topic: Exciton

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	Exciton - Wikipedia, the free encyclopedia
		An exciton is a bound state of an electron and an imaginary particle called an electron hole in an insulator or semiconductor, and such is a Coulomb correlated electron-hole pair.
		Alternatively, an exciton may be thought of as an excited state of an atom or ion, the excitation wandering from one cell of the lattice to another.
		Excitons are thus the main mechanism for light emission in semiconductors at low temperatures (where kT is less than the exciton binding energy), replacing the free electron-hole recombination at higher temperatures.
	en.wikipedia.org /wiki/Exciton (844 words)

	Text of MIJ-NSR Volume 8, Article 3
		Physically, the exciton Bohr radius is analogous to the hydrogen atom's Bohr radius, it is proportional to the average distance between electron and hole for the ground exciton state.
		The clearest signature of exciton Bose condensation should be the emission of a coherent light by spontaneous recombination of condensed excitons [40].
		The polariton dispersion relation of the microcavity for small wave vectors and for zero detuning between the exciton and the cavity mode is obtained by the scattering state method as shown on figure 3-b.
	nsr.mij.mrs.org /8/3/text.html (10375 words)

	IRC#physics-maze#exciton (Site not responding. Last check: 2007-10-20)
		An exciton is made up of an electron and a "hole" These have opposite electric-charge and attract each other -- they can be thought of as orbiting each other.
		Because of their mutual attraction, an exciton is more (energetically) favourable than being free for the electron and hole to be in.
		Because the exciton is an electron orbiting a lack of an electron, it is possible for the electron to jump into the hole, causing the exciton to vanish.
	www.moo.uklinux.net /kinsler/ircph/maze/exciton.html (168 words)

	Wichard JD Beenken Conjugated Polymers
		Particularly the excitons in photosynthetic light-harvesting antenna systems are in the focus of active research.
		The resulting potential surfaces depend on two parameters: v which represents the strength of the excitonic coupling and Δ which represents the difference in the transition energies of the monomers, both in units of the Stokes shift of the monomers.
		Exciton dynamics for the lower exciton in the case v = 0.5 and Δ = 0.1.
	www.tbi.univie.ac.at /~wichard/excitons.htm (775 words)

	Quantum Dot Core Concepts
		An exciton is the term used to describe the electron-hole pair created when an electron leaves the valence band and enters the conduction band.
		Excitons have a natural physical separation between the electron and the hole that varies from substance to substance; this average distance is called the Exciton Bohr Radius.
		In a large semiconductor crystal, the Exciton Bohr Radius is small compared to the crystal, and the exciton is free to wander throughout the crystal.
	www.evidenttech.com /qdot-definition/quantum-dot-glossary.php (1324 words)

	3D exciton and biexciton in cubic QD
		The binding of the electron and the hole in a quantum dot is primarily due to the conduction and valence band confinement.
		The magnitude of this energetic correction strongly depends on the size of the quantum dot and the height of the confining barriers.
		The following figure shows the exciton correction due to the Coulomb iteraction of the lowest electron state with the highest heavy hole state in cubic InAs quantum dots as a function of quantum dot size (4 nm / 6 nm / 8 nm / 10 nm / 12 nm / 16 nm / 20 nm).
	www.wsi.tu-muenchen.de /nextnano3/tutorial/3Dtutorial_QD_exciton.htm (863 words)

	Coherent Exciton Matter -- Physics News Update 800
		Excitons are tiny paired artificial objects adrift in a semiconductor and consist of an electron excited from its home orbital plus a vacancy left behind.
		In the UCSD experiment, the excitons live much longer than usual -- long enough to study as if there were a species of atom -- since the pair partners are held somewhat apart in nano-size structures (quantum wells) in the body of the semiconductor sample.
		The excitons can move about in the plane of the quantum well semiconductor structure and, in a 20-micron-wide ring, constitute a sort of gas which can be cooled down to ultralow temperatures.
	www.aip.org /pnu/2006/split/800-1.html?source=rsspnu (413 words)

	The Travels of An Exciton
		Excitons produce the light in light emitting diodes (LEDs) and in laser diodes found in CD players and laser pointers.
		Like all quantum-scale particles, an exciton does not exist at a single point but is described by a wave--or wave function--that gives the probability of finding it in any given location.
		Each light pulse created a single exciton and biexciton on the dot, and the team used the same fiber to collect the light released with each death of the particles.
	focus.aps.org /story/v12/st15 (627 words)

	Quantum Dot Core Concepts
		The raised electron and the hole taken as a pair are called an exciton.
		Excitons have an average physical separation between the electron and hole, referred to as the Exciton Bohr Radius this physical distance is different for each material.
		However, if the size of a semiconductor crystal becomes small enough that it approaches the size of the material's Exciton Bohr Radius, then the electron energy levels can no longer be treated as continuous - they must be treated as discrete, meaning that there is a small and finite separation between energy levels.
	www.evidenttech.com /qdot-definition/quantum-dot-introduction.php (1211 words)

	Research Highlights: Fluorescence Spectroscopy and Exciton Dynamics of Single Allophycocyanin Trimers
		One of the interesting applications of single-molecule spectroscopy is the study of the exciton dynamics of molecular aggregates, which have been explored by a few groups.
		The exciton trap formation and/or photobleaching of an individual APC trimer is over an order of magnitude faster for pulse than for cw excitation, indicating nonlinear mechanisms for exciton trap formation and/or photobleaching.
		The exciton traps are long-lived and spontaneously reversible.
	www.emsl.pnl.gov /homes/csd/sms/subhomes/r7.html (1016 words)

	Exciton: technologies
		In addition, Exciton carries out contract RandD for both fluorescent and absorber dyes and dye stabilizers for applications ranging from fluorescent tags, to OLEDs, to neon cut filters, to color gamut filters, to optical recording media, to telecommunications materials.
		High purity is critical in laser dyes for maximizing dye laser output, in sensitizing dyes for photolithographic applications, and in absorbing dyes where impurities can lead to losses in luminous transmission or may introduce haze or scattering in laser filters.
		Exciton's facilities include both glass and stainless steel reactors for the production of dye intermediates and dyes, as well as associated products, such as quadricyclane, which are produced by a photochemical process.
	www.exciton.com /tech.html (174 words)

	AN EXCITING NEW STATE FOR EXCITONS
		The creation of a new exciton condensate was reported in the August 15, 2002 issue of the journal Nature, in a paper co-authored by Butov, Arthur Gossard of UC Santa Barbara's Department of Electrical and Computer Engineering, and Daniel Chemla, director of Berkeley Lab's Advanced Light Source.
		The new exciton condensate was observed at Berkeley Lab using photoluminescence on samples composed of the semiconductors gallium arsenide and aluminum gallium arsenide.
		Under photoluminescence, the macroscopically ordered exciton state that Butov and his colleagues observed appeared against a fl background as a bright ring that had been fragmented into a chain of circular spots extending out to one millimeter in circumference.
	www.lbl.gov /Science-Articles/Archive/MSD-Bose-Einstein-Butov.html (591 words)

	Proceedings of the Oklahoma Academy of Science
		For the parallel polarization (resonant scattering with the B exciton), resonant enhancement is also observed along with a small frequency dispersion of the longitudinal phonon.
		This bound exciton results from the B exciton becoming bound to a neutral donor atom in the crystal.
		By temperature tuning the A and B exciton states toward a fixed laser frequency, we have observed the expected resonant enhancement and dispersion of the longitudinal acoustic phonon, in addition to the forbidden transverse acoustic phonon.
	digital.library.okstate.edu /OAS/oas_htm_files/v71/p25_28nf.html (1956 words)

	Groovecube's Exciton softsynth review
		Exciton is currently the only softsynth from Groovecube.
		Exciton is facing pretty stiff competition, and let me say that this one is a winner sound wise.
		I went for Exciton instead for about the tenth of the price of pretty much any VA hardware, thank you very much.
	www3.sympatico.ca /sdelisle/exciton_review.html (2572 words)

	OER April '95 -- Optical processor operates through exciton transport
		This transportation of the original excitation energy (exciton) is possible because the fluorescence spectrum of each layer overlaps with the absorption spectrum of its neighbor down the line.
		In fact, this method of transforming energy from one form to another is quite similar to photosynthesis, which uses a stack of chromoproteins within the plant to perform the same function.
		This means it can accept an exciton from the OCC and pass it down to the IDC layer (see figure 2).
	www.spie.org /web/oer/april/exciton_trans.html (731 words)

	ONE-SHOTS
		Programmed by Yuji Miyane, Exciton's tight housing of two identical oscillators, built-in effects and a multitude of filter-shaping options delivers a functional and compellingly original sonic flavor.
		Like any good synth, Exciton can get weird, nasty and plain unlovable — only to turn the corner with a single tweak of a knob and thus transform into something altogether wonderful.
		However, pitting Exciton against the lot of VST Instruments, the newcomer shines with originality.
	remixmag.com /tech/sound_collections/remix_oneshots_5 (832 words)

	KVR: Groovecube Technologies Exciton - Virtual Instrument
		There is Reaktor too, the monster synth, but I say that Exciton's sound in mouch cleaner, the filter is also great, and there is the saturation too (the saturation is a little cheap, and may need some fixes).
		It looks like FL is sending some reset signals, because Exciton periodically returns to it's default preset.
		They are both comparable products (it's not like comparing it with Reaktor or Absynth for instance which are too different), and in my opinion, Exciton is supperior in every points: quality of the oscillators, of the filters, modulation, interface, etc. Two thumbs up.
	www.kvraudio.com /get/398.html (1095 words)

	Recent Results of Exciton BEC (Site not responding. Last check: 2007-10-20)
		The observed large enhancement of the effective mass of the indirect exciton in magnetic fields is a sigle-exciton effect contrary to the well known renormalization effects in neutral and charged e-h plasmas.
		It has,, however, very important effects on collective phenomena in the exciton system.
		In particular, the mass enhancement explains the disappearance of the stimulated exciton scattering and the transition from the highly degenerate to classical exciton gas with increasing magentic field observed in [Butov 2001]
	www.lbl.gov /chemla/research/ExcitonBEC.html (94 words)

	Squarepusher - Exciton – Music at Last.fm
		Labels and artists can upload their music here…
		Pick a Word When more people add tags for Exciton, a tag cloud will appear here.
		Music Journals on Last.fm You can be the first person to write a journal about Exciton.
	www.last.fm /music/Squarepusher/_/Exciton (97 words)

	Bose-Einstein condensation of exciton polaritons : Abstract : Nature
		Bose-Einstein condensation of exciton polaritons : Abstract : Nature
		Much effort has been devoted to finding a solid-state system in which BEC can take place.
		Promising candidate systems are semiconductor microcavities, in which photons are confined and strongly coupled to electronic excitations, leading to the creation of exciton polaritons.
	www.nature.com /nature/journal/v443/n7110/abs/nature05131.html (318 words)

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