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The accuracy of different transfer matrix approaches, which are used for solving the stationary effective mass Schrodinger equation for arbitrary one-dimensional potentials, is examined. Analytical model potentials as well as self-consistent Schrodinger-Poisson simulations of a heterostructure device have shown that a symmetrized transfer matrix approach has produced a similar accuracy as the Airy function method at a reduced numerical cost, thus avoiding the numerical problems associated with Airy function.

A series of high-mobility [Al.sub.0.12][In.sub.0.88]Sb/InSb heterostructures are grown by molecular beam epitaxy to examine the fabrication of micro-Hall magnetic field sensors. The results have shown that the utility of devices with larger devices has led to magnetic field detection in the pT range at low temperatures and sub-nT range even at room temperature.

An alternative guided-wave optical interconnection architecture, based on using prismatic coupling elements, is described for enabling high-efficiency coupling into and out of an underlying multiple-quantum-well (MQW) modulator. The ray-trace and finite-difference time-domain simulation results have shown high coupling efficiency of the prism coupling structure.

A charge control model is developed for the transient analysis of the bipolar transistor laser in forward active mode in order to describe the dynamics of electron, photon and charge densities. The analysis of laser switching has shown that the turn-on time is reduced by increasing the base current or decreasing the spontaneous emission lifetime of electrons in the quantum well.

A method based on finite-difference mode convergence technique is described for analyzing nonlinear multilayered-planar waveguides and multiple-quantum-well structures. Many waveguide structures are analyzed in order to test the accuracy and establish the efficacy of the algorithm as a useful analysis recipe for modeling and understanding the modal properties of nonlinear multilayered waveguides.

Commercially available quantum-well infrared focal plane array (FPA) is compared with a custom quantum-dot (QD)-in-a-well (DWELL) infrared FPA in the long-wave infrared (LWIR). The quantum-well FPA has displayed a higher collection efficiency of 1.3 when compared to the DWELL.

A continuously tunable semiconductor disk laser with intracavity second-harmonic generation (SHG) is evaluated using a wedged and antireflection-coated diamond heatspreader. Findings reveal output powers of more than 600 mW tunable over 10 nm around 530 nm.

A study on the polarized light emission from semipolar GaInN quantum wells on {1101} GaN facets was conducted. The results revealed that the light is linearly polarized parallel to the stripes representing the direction of the GaN crystal due to strain induced valence band splitting depending on the crystal orientation.

The electronic and optical properties of germanium-rich Si/SiGe quantum wells grown on [Si.sub.0.5][Ge.sub.0.5] substrates are examined by a nearest neighbor tight-binding Hamiltonian. The results for group IV conduction intersubband transitions might help in the project of devices for terahertz applications.

The carrier distribution and its dependence on barrier thickness are investigated by using the transition cavity length method and the temperature varying photoluminescence (PL) spectra for the mirror image asymmetric multiple quantum well structures. The dominant role that the carrier diffusion across the barrier plays leads to the dependence of the carrier distribution on the barrier thickness.

Time-resolved photoluminescence measurements is carried out for InAs quantum dots (QDs) coupled through a GaAs barrier to an In0.3Ga0.7As quantum well (QW). A rate equation model is developed to describe the observed behavior through carrier capture from QW to QD states in the QD:QW structure.

The effects of a growth-direction applied magnetic field on the cyclotron effective masses and electron effective Lande [g.sub.II] factor in semiconductor GaAs-[Ga.sub.1-x][Al.sub.x]As quantum wells (QWs) are theoretically evaluated. The calculations are performed for different widths of the QWs and as functions of the applied magnetic field, with results in good agreement with experimental measurements of the electron cyclotron effective mass and [g.sub.II] factor.

Spin relaxation under identical Dresslhaus and Rashba coupling in GaAs quantum wells is studied in both the traditional collinear statistics. It is shown that there is only marginal difference between the spin relaxation times obtained from these two different statistics.

A theoretical study of the near gap electronic states of Si/Ge based multiple quantum well system composed of Si and Si (sub 1-x)Ge (sub x) alloys coherently grown on (001)-Si or SiGe substrates is presented. The calculations give an accurate description of the near gap experimental photoluminescence peaks.

The band structures of wurtzite ZnO are calculated by the empirical pseudopotential method (EPM). The eight parameters of the Zn and O atomic preudopotential form factors are obtained.

High-resolution x-ray diffraction (HRXRD) and photoluminescence is used to study the diffusion of atoms in 8-nm Ga(sub 0.628)In(sub 0.372)N(sub 0.015)As(sub 0.985)/GaAs quantum well, with and without dielectric encapsulants. HRXRD simulations demonstrate that the diffusion lengths are shorter than 2 nm under the annealing conditions studied.

(Received 25 June 2005; accepted 21 October 2005) We investigate the problem of a quantum particle in a one-dimensional finite square well. In the standard approach the allowed energies are determined implicitly as the solutions to a transcendental equation. We obtain the spectrum analytically as the solution to a pair of parametric equations and algebraically using a remarkably accurate approximation to the cosine function. The approach is also applied to a variety of other quantum wells.

Pseudomorphic four-period GaAs0.978N0.022/GaAs0.78Sb0.22 type-II multi-quantum well structures were grown on (100) GaAs substrates by metalorganic vapor phase epitaxy (MOVPE). Photoluminescence (PL) peak energies were obtained from GaAsN/GaAsSb type-II superlattive structures grown by MOVPE.

A comprehensive theoretical study of the ultrafast optical manipulation of electron spins in quantum wells is presented based on a multiparticle-state stimulated Raman adiabatic passage approach. Also the effects of hole-spin relaxation in the valence band will be analyzed in detail.

Laser gain is investigated for AlGaN wurtzite quantum-well structures emitting in the wavelength range from ~270 to 340 nm. The calculations show that gain properties vary notably with aluminum concentration in the quantum well.

Effective masses of holes in In(sub 0.36)Ga(sub 0.64)As(sub 1-x)N(sub x)/GaAs quantum well structures were determined and analyzed. The result shows that significant variation in the effective masses is possible by adjusting the relevant parameters.

A theoretical investigation on the time evolution of spin pulses in an n-type GaAs (001) quantum well with and without external electric field at high temperatures by constructing and numerically solving the kinetic spin Bloch equations and the Poisson equation with the electron-phonon, electron-impurity, and electron-electron Coulomb scatterings explicitly included. The results obtained are consistent in bulk GaAs but at very low temperature (4 K) by Crooker and Smith.

The symmetry-based calculations of the spin structure of excitons and biexcitons in quantum well is reported. Hamiltonians appropriate are derived for the description of excitons and biexcitons depending on the point-group symmetry of the material and the growth directions of the quantum wells.

The dependence of the intersubband absorption spectra on the Coulomb interaction and quantum well (QW) width is examined. It is shown that the line shape and peak position of the intersubband absorption spectra are the results of the interplay of various many-body effects and also the QW width and subband effective masses alter the line shape and peak position of the spectra.

A theoretical model and a design of a magnetic-field tunable CdMnTe/CdMgTe terahertz quantum well infrared photodetector are presented. A perpendicular magnetic field varying between 0 and 5 T, at a temperature of 1.5 K, is found to enable a large shift of the detection energy, yielding a tuning range between 24.1 and 34.3 meV, equivalent to 51.4-36.1 mum wavelengths.

In0.17GaAs/GaAsP0.06 multiquantum well structures, together with secondary electron microscopy are characterized using ultrahigh vacuum cross-sectional Kelvin probe force microscopy. Individual 8 nm quantum wells are well resolved in both methods, and are found to be in good agreement with numerical simulations of the work function profile.

Multiple component decays of photoluminescence (PL) in InGaN/GaN quantum wells are widely reported. Free exciton behaviors of the three samples at high temperatures are consistent with previously reported transmission electron microscopy results.

The technique of controlled group V quantum well intermixing (QWI) in a compressively strained In(sub 0.76)Ga(sub 0.24)As(sub 0.85)P(sub 0.15)/In(sub 0.76)Ga(sub 0.24)As(sub 0.52)P(sub 0.48) multiquantum well laser structure and its application to the fabrication of two section tunable lasers is reported. A tuning range of about 10 nm was demonstrated by simply changing the current injected into the phase tuning section.

The use of finite confining potential well model for excitons in a cylindrical quantum wire indicated that for wire radii greater than a few Bohri radii, the contribution to the exciton linewidth calculated using this model agrees with the results for the infinite well model. However for smaller wire radii, the linewidth reaches a maximum value and then decreases due an increasing probability that the exciton would be found outside the wire in the surrounding barrier.

An enhanced k-p optical calculation framework, based on the intracell interactions, is used to study the effects of bulk inversion asymmetry (tetrahedral) on the optical transitions of zinc blende semiconductor quantum wells. The study is found to be not very accurate for the calculations, as it does not reveal the variation in the optical transition strength of the complexes, which is mainly attributed to the inversion asymmetry of the substance.

The in-plane optical anisotropy (IPOA) of asymmetric (001) GaAs/AlGaAs quantum wells (QWs) is investigated, where the asymmetry is introduced via the insertion of a monolayer of InAs or AlAs at the interfaces of the QWs. The results show that the insertion of monolayer material at interfaces provides a convenient way to control IPOA in (001) QWs.

A complete analysis of the enhancement taking place in the hole confinement in the GaInAsN-aAsSbN thin double-layer quantum-well structure is presented. The electrons are shown to be less confined as carriers, in comparison to the bilayers structure.

Intersubband absorption energy shifts in 3-level system stemming from depolarization and excitonlike effects are examined. Temperature character of depolarization and excitonlike shift (DES) in the step well structure is analyzed and are applied to calculate asymmetric step quantum well structures.

The carrier transfer between quantum dot (QD) and quantum well (QW) layers is analyzed in a hybrid dot-well system based on InAs QDs and InGaAs QWs. Strong state-filling effects of the excited QD states have affected the carrier transfer efficiencies.

The optical properties of a-plane ZnO/ZnMgO multiple quantum wells (MQWs) structure grown by the pulse laser deposition system are analyzed. The emission peak energy of a-plane ZnO/ZnMgO MQWs is kept invariant in the power-dependent photoluminescence (PL) measurement, which has shown the nonpolar characteristics due to the lack of built-in electric fields.

Several theoretical studies are conducted to explain the application of the different staggered quantum well structures for enhancing the output power and performance of the blue InGaN light-emitting diodes. The optimum design of the staggered quantum well required for taking out the best optical characteristics of these diodes is also discussed.

The article presents a complete analysis of the various nanostructured work function electrodes that are formed from a metal layer and a base substrate. The application of these electrodes for different thermionic and thermotunnel devices is also discussed.

An epitaxied AlGaAs/GaAs/AlGaAs heterostructure is analyzed by using the low frequency noise technique over a wide range of temperature as function of bias. Thermal activation energies and capture cross sections of traps responsible for the generation-recombination noise are extracted from an Arrhenius plot.

The linear and nonlinear optical response of intersubband transitions in a semiconductor quantum well is described. The coupling of the quantum well structure with the electromagnetic field is described by using the nonlinear density matrix equations, in the two-subband approximation.

A new optoelectronic measurement of quantum well (QW) thickness is described and it is applied to doped and undoped [In.sub.0.53][Ga.sub.0.47]As/[In.sub.0.52][Al.sub.0.48]As multiple-QW structures. The QW thicknesses have agreed well with the QW thicknesses estimated by double-crystal x-ray diffraction within almost two monolayers, which are used for determining the distance of potential boundaries confining the electron wave functions.

Several studies are conducted to explain the photoluminescence and emission variation exhibited by the different InAs quantum dots coupled with the symmetric quantum wells. The various factors leading to differences in the emission intensities are also identified.

Transfer-matrix method is used for examining the transport properties of a graphene multiqunatum well system. Tiny oscillation of the conductance and fine structures in the middle energy range are because of the resonant tunneling induced by the multiquantum well structure.

Exciton localization in ZnO/[Mg.sub.x][Zn.sub.1-x]O quantum wells (QWs) is examined with various ZnO well widths for the fixed [Mg.sub.0.23][Zn.sub.0.77]O barrier height. The band characteristics and strong exciton localization in ZnO/[Mg.sub.0.23][Zn.sub.0.77]O QWs are attributed to the fluctuations associated with the inhomogeneous broadening.

The effect of a nonsharp and disordered potential in quantum well infrared photodetectors (QWIP is studied. The studies have shown that QWIP properties are very robust with regard to the nonideality of the energy band profile.

The nonlinear intersubband response of multiple-quantum-well structures embedded in microcavities with plane-wave approximation is discussed. It is shown that the strong-coupling-regime the saturation effect has led to the evolution of the adsorption spectra from a pair of simple harmonic oscillators to highly anharmonic ones.

The article discusses a newly developed Aharonov-Bohm (AB) system, which is completely based on the various electron-hole bilayer nanotubes made of rolled-up type-II band aligned quantum wells. These nanotubes are shown to be widely used for a large number of magneto-optical switching devices and similar applications.