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Admittance spectroscopic analyses of lattice-mismatched InAlAs InGaAs single-quantum-well semiconductors show that the temperature dependency of the space-charge region width governs the perpendicular conductivity of the semiconductor. A high density of deep electron traps in the layers near the quantum well controls the entire process, thus accounting for the strong influence of deep-level defects on the energy activation of the perpendicular conductivity. Thus, admittance measurements are incapable of yielding the value of the magnitude of band offset.

Molecular beam epitaxy facilitated the growth of erbium-doped and ytterbium-doped GaAs to reveal the existence of rare earth related traps. These traps corresponded to the difference between the activation energy and the corresponding gap energy that were observed using photoinduced current transient spectroscopy measurements. Rare earth impurities on III-V semiconductors materials are incorporated in several emitting devices.

We show how the height dispersion of self-organized InAs/InP(001) quantum islands emitting at 1.55 μm was reduced by optimizing the epitaxial growth parameters. Low height dispersion was obtained when the InAs deposit thickness was much greater than the critical thickness for two-dimensional/three-dimensional growth mode transition, and when adatom surface diffusion was favored by increasing the growth temperature or reducing the arsenic pressure during the InAs growth. When these growth conditions are not respected, the multicomponent photoluminescence spectrum obtained is explained through the common interpretation of island height varying with monolayer fluctuation. In optimized growth conditions, the multicomponent spectrum obtained is interpreted as emission from fundamental and excited levels of InAs islands with low height dispersion. Transmission electron microscopy (TEM) imaging shows that these InAs islands are stick-like, 50–100 nm in length and 22±1.2 nm in width. Cross-sectional TEM reveals flat islands, shaped like truncated pyramids, with a very homogeneous height measured at 2.4 nm. A fundamental level linewidth of 22 meV at 8 K is associated to this very narrow height distribution. Such low photoluminescence linewidth values are believed to be mainly due to the propensity of the InAs/InP(001) system to produce flat InAs islands with discrete height fluctuation. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have investigated light propagation through a single line-defect photonic crystal waveguide on a InP membrane. Modal analysis was performed using the finite-difference time-domain method. The fundamental mode has been found to be very close to the fundamental mode in a "refractive" waveguide but, in this case, it is inherently leaky. The propagation losses of this mode in the complete three-dimensional structure have been computed and measured to determine if its use could be of interest for practical applications. Propagation losses in the range of 0.1 dB/µm have been found numerically and experimentally for the fundamental mode whereas stronger out-of-plane losses have been observed for the other leaky mode within the band gap. The origins of the out-of-plane losses were then investigated and have clarified the inherent lower leakage of the fundamental mode. [ABSTRACT FROM AUTHOR]

InAs nanostructures were grown on In[sub 0.52]Al[sub 0.48]As alloy lattice matched on InP(001) substrates by molecular beam epitaxy using specific growth parameters in order to improve island self-organization. We show how the change in InAs surface reconstruction via growth temperature from (2 × 4) to (2 × 1) and/or the use of InAlAs initial buffer surface treatments improve the island shape homogeneity (either as quantum wires or as quantum dots). Differences in island shape and in carrier confinement are shown by atomic force microscopy and by photoluminescence measurements, respectively. We point out that such shape amendments induce drastic improvements to island size distribution and discernible changes in photoluminescence properties, in particular concerning polarization. [ABSTRACT FROM AUTHOR]

An optical modulation technique of photoreflectance (PR) at room temperature is used in the study of Lattice-matched and strained InGaAs/InAlAs single quantum wells, where x has values of 0.53 and 0.60. Interband transitions from the heavy- and light-hole valence subbands to the conduction subbands are observed from the measurements.

Stick-like InAs islands on InP (001) emitting at 1.55 micro m with high density and low height dispersion by optimizing the epitaxial growth parameters of InAs' island layer is shown. High uniformity, high density and thermal stability of the InAs are expected to give a strong enough optical gain to develop highly efficient microlasers emitting at 1.55 micro m.

Research is done on carrier confinement in InAs quantum dashes (QDas) grown on InP(001), which is examined both experimentally and theoretically. In conclusion, combining experimental and theoretical results, an interpretation is proposed of the optical transitions occurring in these QDas and we give a first theoretical absorption spectrum of these structures.

Studies the admittance spectroscopy of InAlAs/InGaAs single-quantum-well (QW) structure with high concentration of electron traps in InAlAs layers. Factor that controls the perpendicular conductivity of the structure; Temperature dependence of the space-charge region width around the QW layer; Origin of the unusual behavior in the admittance spectra of the QW structure.

Presents a study which investigated the optical properties of ultrathin InAs/InP quantum wells grown by hydride vapor-phase epitaxy. Information on the epitaxial growth; Details of the photoluminescence investigation; Conclusion.

The light propagation through a single line-defect photon crystal wave-guide on an InP membrane is detailed. The propagation loses on the fundamental mode in the complete three dimensional structure are in the range of 0.1 dB/micron meter.