Low-and room-temperature optical absorption spectra are presented for a series of InAs x P 1Ϫx /InP strainedlayer multiple quantum well structures ͑0.11 рxр0.35͒ grown by low-pressure metal-organic vapor phase epitaxy using trimethylindium, tertiarybutylarsine, and phosphine as precursors. The well widths and compositions in these structures are exactly determined from the use of both high-resolution x-ray diffraction and transmission electron microscopy on the same samples. The absorption spectra are then analyzed by selfconsistently fitting, for the five samples, the excitonic peak energy positions with transition energies determined from a solution to the Schrödinger equation in the envelope function formalism using the well-known Bastard/Marzin model ͓J. Y. Marzin et al., in Semiconductors and Semimetals, edited by Thomas P. Pearsall, ͑Academic, New York, 1990͒, Vol. 32, p. 56͔. From these self-consistent fits, both the bowing parameter of bulk unstrained InAs x P 1Ϫx and the band offsets of the heterostructures are deduced self-consistently. The conduction-band offsets thus determined represent 75%Ϯ3% of the total strained band-gap differences at both low ͑liquid He͒ and room temperatures. These values of the band offsets are consistent with the predictions of the quantum dipole model ͓J. Tersoff, Phys. Rev. B 30, 4874 ͑1984͔͒. The values determined for the bowing parameters are found to differ slightly between 0.10Ϯ0.01 eV at low temperature and 0.12Ϯ0.01 eV at room temperature.

A detailed investigation of the structural and optoelectronic properties of thick GaInP epilayers on sulfur-doped InP substrates is reported. Significant variations of the optical absorption and photoluminescence transition energies from light- and heavy-hole states are observed as a function of the epilayer composition as well as of the degree of relaxation of the misfit strain. High-resolution x-ray measurements were used to determine the Ga concentrations and the strains and indicate significant anisotropic relaxation in several films. Even small relaxations result in a significant increase in the optical linewidths and a rapid drop in the transition intensities. A model with no free parameters based on the strain Hamiltonian of Pikus and Bir provides excellent agreement with the transition energies and serves to identify unambiguously the transitions observed in the optical spectra. Within this model, isotropic in-plane relaxation produces a shift of both light- and heavy-hole energies whereas anisotropic in-plane relaxation contributes only negligibly.

The development of a low pressure, horizontal MOCVD (metal-organic chemical vapour deposition) reactor has allowed us to study the effect of phosphine and trimethylindium molar fluxes on the epitaxial growth of InP. Study of the growth rate in the temperature range 550–620 °C shows that the growth can be limited by the reaction kinetics at the surface. Epitaxial layers of good morphological quality have been obtained by reducing the rate of growth even if the growth is limited by the reaction kinetics at the surface. The variation of the electronic mobility with the PH3 molar flux reveals the existence of an optimum mobility region, even with a constant V: III ratio. Photoluminescence experiments carried out on the samples show the good crystallographic quality of the epitaxial layers. Spectra taken in the energy range 0.8–1.2 eV show the evolution of two structures at 0.91 and 1.08 eV that we associate with an antisite PIn and a VIn defect, respectively.[Journal translation]

We report low temperature optical absorption measurements on GaxIn1−xP/InP (x<0.2) multiple quantum wells and strained-layer superlattices. The spectra show several well-defined peaks whose positions can be fitted within an envelope-function formalism including strain effects. We deduce conduction band offsets between the larger gap ternary and smaller gap binary materials ranging from 30 to 50 meV. Since these values are intermediate between the strain-induced shifts for the light- and heavy-hole valence bands, the electrons and heavy holes are localized in the InP layers (type I system), whereas the light holes have their quantum wells in the GaInP layers (type II system).

Low temperature optical absorption spectra are presented for a series of InAsxP1-x/InP strained layer multiple quantum well structures (0 < x = 0.35) grown by low pressure metal organic vapor phase epitaxy (LP-MOVPE) using trimethylindium (TMIn), tertiarybutylarsine (TBAs) and phosphine as precursors. The well widths and compositions in these structures are determined from high resolution x-ray diffraction and transmission electron microscopy. The absorption spectra are then analyzed by fitting the excitonic peak energy position with transition energies determined from a solution to the Schrödinger equation. We used the envelope function formalism with the Kane bands as the basis wavefunctions and included corrections for non parabolicity. From these fits and elasticity theory, both the bandgap of unstrained InAsxP1-x and the band offsets of these heterostructures are deduced self-consistently. The conduction band offsets are found between 72% and 75% of the total strained bandgap differences.