Polarization Insensitivity in Interdiffused, Strained InGaAs/InP Quantum Wells

1996 ◽  
Vol 450 ◽  
Author(s):  
Joseph Micallef ◽  
James L. Borg ◽  
Wai-Chee Shiu
Keyword(s):  
Absorption Coefficient ◽  
Quantum Wells ◽  
Error Function ◽  
Fundamental Absorption Edge ◽  
Group V ◽  
Group Iii ◽  
Interdiffusion Process ◽  
Excitonic Transition ◽  
Polarization Insensitive ◽  
Polarization Insensitivity

ABSTRACTTheoretical results are presented showing how quantum well disordering affects the TE and TM absorption coefficient spectra of In0.53Ga0.47As/InP single quantum wells. An error function distribution is used to model the constituent atom composition after interdiffusion. Different interdiffusion rates on the group V and group III sublattices are considered resulting in a strained structure. With a suitable interdiffusion process the heavy hole and light hole ground state, excitonic transition energies merge and the absorption coefficient spectra near the fundamental absorption edge become polarization insensitive. The results also show that this polarization insensitivity can persist with the application of an electric field, which is of considerable interest in waveguide modulators.

On quantifying the group-V to group-III interdiffusion rates in InxGa1−xAs/InP quantum wells

2006 ◽  
Vol 21 (6) ◽  
pp. 829-832 ◽  
Author(s):  
P L Gareso ◽  
M Buda ◽  
H H Tan ◽  
C Jagadish ◽  
S Ilyas ◽  
...  
Keyword(s):  
Quantum Wells ◽  
Group V ◽  
Group Iii

Cation Interdiffusion in GaInP/GaAs Single Quantum Wells

1997 ◽  
Vol 484 ◽  
Author(s):  
Joseph Micallef ◽  
Andrea Brincat ◽  
Wai-Chee Shiu
Keyword(s):  
Quantum Wells ◽  
Large Strain ◽  
Error Function ◽  
Fundamental Absorption Edge ◽  
Red Shift ◽  
Material System ◽  
Single Quantum ◽  
Carrier Confinement ◽  
Device Applications ◽  
Cation Interdiffusion

AbstractThe effects of cation interdiffusion in Ga0.51In0.49P/GaAs single quantum wells are investigated using an error function distribution to model the compositional profile after interdiffusion. Two interdiffusion conditions are considered: cation only interdiffusion. and dominant cation interdiffusion. For both conditions the fundamental absorption edge exhibits a red shift with interdiffusion, with a large strain build up taking place in the early stages of interdiffusion. In the case of cation only interdiffusion, an abrupt carrier confinement profile is maintained even after significant interdiffusion, with a well width equal to that of the as-grown quantum well. When the interdiffusion takes place on two sublattices. but with the cation interdiffusion dominant, the red shift saturates and then decreases. The model results are consistent with reported experimental results. The effects of the interdiffusion-induced strain on the carrier confinement profile can be of interest for device applications in this material system.

scholarly journals MBE Growth of Nitride-Arsenide Materials for long Wavelength Opto-electronics

2000 ◽  
Vol 5 (S1) ◽  
pp. 474-480 ◽  
Author(s):  
Sylvia G. Spruytte ◽  
Christopher W. Coldren ◽  
Ann F. Marshall ◽  
Michael C. Larson ◽  
James S. Harris
Keyword(s):  
Quantum Wells ◽  
Molecular Nitrogen ◽  
Nitrogen Concentration ◽  
Plasma Source ◽  
Lattice Parameter ◽  
Nitrogen Plasma ◽  
Group V ◽  
Mbe Growth ◽  
Group Iii ◽  
Nitrogen Concentrations

Nitride-Arsenide materials were grown by molecular beam epitaxy (MBE) using a radio frequency (rf) nitrogen plasma. The plasma conditions that maximize the amount of atomic nitrogen versus molecular nitrogen were determined using the emission spectrum of the plasma. Under constant plasma source conditions and varying group III flux, the nitrogen concentration in the film is inversely proportional to the group III flux (i. e. the nitrogen sticking coefficient is unity). The relationship between nitrogen concentration in the film and lattice parameter of the film is not linear for nitrogen concentrations above 2.9 mole % GaN, indicating that some nitrogen is incorporated on other locations than the group V lattice sites. For films with these higher nitrogen concentrations, XPS indicates that the nitrogen exists in two configurations: a Gallium-Nitrogen bond and another type of nitrogen complex in which nitrogen is less strongly bonded to Gallium atoms. Annealing removes this nitrogen complex and allows some of the nitrogen to diffuse out of the film. Annealing also improves the crystal quality of GaAsN quantum wells.

Chemical Beam Epitaxy of III-V Semiconductor Heterostructures

1987 ◽  
Vol 102 ◽  
Author(s):  
W. T. Tsang
Keyword(s):  
Quantum Wells ◽  
Molecular Beam ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Chemical Beam Epitaxy ◽  
Group V ◽  
Group Iii ◽  
Group Iv Semiconductors ◽  
Gas Source Mbe

ABSTRACTThis paper reviews briefly some of the recent progress in chemical beam epitaxy (CBE) for the preparation of GaInAs(P)/InP and GaAs/AlGaAs quantum wells, superlattices, and heterostructure devices. Chemical beam epitaxy can be viewed as a chemical vapor deposition process but with the pressure inside the growth chamber sufficient, ow (< 10-4 torr) so that the transport of the gaseous reactants becomes molecular beam instead of via viscous flow. This not only eliminates the complicated gas phase reactions and the stagnant boundary layer above the substrate through which the reactants have to diffuse, but also allows for quick transitions of material compositions and dopings as those achievable by molecular beam epitaxy (MBE). For the growth of HI-V semiconductors, the group Inl elements are derived by the pyrolysis of organometallics (or inorganometallics such as dopant gases) on the heated substrate surface, while the group V elements are derived by the thermal decomposition of hydrides using a high temperature cracker. For the growth of group IV semiconductors, beams of inorganometallic compounds are used. Thus, both organometallic and inorganometallic compounds can be used as starting sources. There are two other alternatives: the gas source MBE (GSMBE), which uses group III elements evaporated from solid sources as in MBE and thermally decomposed hydrides, and the metalorganic MBE (MOMBE), which uses metalorganics as group III sources and group V elements evaporated from solid sources as in MBE. These other processes will not be reviewed here. Introd

Self-Induced Photon Absorption by Screening of the Electric Fields in Nitride-based Quantum Wells

2002 ◽  
Vol 743 ◽  
Author(s):  
S. Kalliakos ◽  
P. Lefebvre ◽  
T. Taliercio ◽  
B. Gil
Keyword(s):  
Absorption Coefficient ◽  
Quantum Wells ◽  
Electric Fields ◽  
Optical Transition ◽  
Optical Excitation ◽  
Blue Shift ◽  
Photon Absorption ◽  
Group Iii ◽  
Excitation Laser ◽  
Group Iii Nitride

ABSTRACTWe have calculated the change of interband absorption spectra of a quantum well based on hexagonal group-III nitride semiconductors under photo-injection of high densities of electron-hole pairs. The screening of internal electric fields by such optical excitation is known to blue-shift and reinforce the ground-state optical transition. Due to the large values of densities of states and of internal fields, we predict novel properties that rather concern optical absorption via transitions between excited states. The absorption coefficient can be strongly enhanced by the optical excitation itself, in this particular spectral region, yielding the possibility for self-induced absorption properties. In other words, if sufficiently intense, an excitation laser can increase the absorption coefficient of the system at its own wavelength, thus providing a strong nonlinear optical response. Finally, we briefly discuss the potential application of these optical phenomena.

The Quantitative Ultrastructure of the Heart Muscle of Japanese Quail by Hypergravitation, Hypodynamy and Combination

1990 ◽  
Vol 48 (3) ◽  
pp. 188-189
Author(s):  
Anton Bózner ◽  
Mikuláš Gažo ◽  
Jozef Dostál
Keyword(s):  
Japanese Quail ◽  
Heart Muscle ◽  
Relative Size ◽  
Combination Group ◽  
Control Group ◽  
Group V ◽  
Group Iii ◽  
Space Flights ◽  
Group I ◽  
Quantitative Ultrastructure

It is anticipated that Japanese quail /Coturnix coturnix japonica/ will provide animal proteins in long term space flights. Consequently this species of birds is of research interest of international space program INTERCOSMOS. In the year 1987 we reported on an experiment /2/ in which the effect of chronic acceleration of 2 G hypergravitation, the hypodynamy and the simultaneous effect of chronic acceleration and the location in the centre of the turntable of the centrifuge on the protein fractions in skeletal muscles was studied. The ultrastructure of the heart muscle was now in this experiments examined as well.Japanese quail cockerels, aged 48 days were exposed to 2 G hypergravitation /group IV/ in a 6,4 m diameter centrifuge, to hypodynamy /group III/ and their combination /group V/, respectively for 6 days / Fig.1/. The hypodynamy in group III was achieved by suspending the birds in jackets without contact the floor. The group II was located in the centre ofthe turntable of the centrifuge. The control group I. was kept under normal conditions. The quantitative ultrastructure of myocard was evaluated by the methods of Weibel/3/ - this enables to determine the number, relative size and volume of mitochondria volume of single mitochondria, defficiency of mitochondrial cristae and volume of myofibrils.

Exciton localization in group-III nitride quantum wells

1999 ◽  
Vol 59 (15) ◽  
pp. 9783-9786 ◽  
Author(s):  
V. I. Litvinov ◽  
M. Razeghi
Keyword(s):  
Quantum Wells ◽  
Group Iii ◽  
Exciton Localization ◽  
Group Iii Nitride
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