No abstract

Articles you may be interested inGaAsSb/GaAsN short-period superlattices as a capping layer for improved InAs quantum dot-based optoelectronics Appl. Phys. Lett. 105, 043105 (2014); 10.1063/1.4891557Molecular-beam epitaxy of phosphor-free 1.3 μ m InAlGaAs multiple-quantum-well lasers on InP (100) Midinfrared InGaAsSb quantum well lasers with digitally grown tensile-strained AlGaAsSb barriers Growth of high-quality GaAs/AlAs Bragg mirrors on patterned InP-based quantum well mesa structuresWe identify quasi-donor-acceptor pair transitions in the photoluminescence spectra of GaAsSb and AlGaAsSb layers, lattice matched to InP, and grown by molecular-beam epitaxy. These alloys show compositional inhomogeneity due to phase separation resulting from miscibility gaps. The presence of Al in the quaternary alloy increases the fluctuation of the electrostatic potential in the epitaxial layer, increasing the variation of recombination energy as a function of intensity excitation in the range of low temperatures.

Photoluminescence and photoreflectance measurements have been used to determine excitonic transitions in the ternary AlxGa1−xAs alloy in the temperature range from 2 to 300 K. The effect of the thermal expansion contribution on the temperature dependence of excitonic transitions for different aluminum concentrations in the AlxGa1−xAs alloy is presented. Results from this study have shown that the negative thermal expansion (NTE) in the AlxGa1−xAs alloy, in the low temperature interval, induces a small blueshift in the optical transition energy. In the temperature range from ∼23 to ∼95 K there is a competition between the NTE effect and the electron-phonon interaction. Using the thermal expansion coefficient in the 2 -300 K temperature range, the thermal expansion contribution to GaAs, at room temperature, represents 21% of the total shift of the excitonic transition energy. After subtracting the thermal expansion contribution from the experimental temperature dependence of the excitonic transitions, in the AlxGa1−xAs alloy, the contribution to the electron-phonon interaction of the longitudinal optical phonon increases, relatively to the longitudinal acoustical phonon, with increasing Al concentration.

No abstract

Rapid thermal annealing effects on step-graded InAlAs buffer layer and In 0.52 Al 0.48 As/In 0.53 Ga 0.47 As metamorphic high electron mobility transistor structures on GaAs substrates Exciton dissociation effects on time resolved photoluminescence measurements of an Al 0.53 In 0.47 P/Ga 0.52 In 0.48 P/Al 0.53 In 0.47 P -quantum well structure J. Appl. Phys. 89, 6426 (2001); 10.1063/1.1366661 Super-flat interfaces in pseudomorphic In 0.72 Ga 0.28 As/In 0.52 Al 0.48 As quantum wells grown on (411)A InP substrates by molecular beam epitaxy Investigation of optical properties of interfaces between heavily doped Al 0.48 In 0.52 As:Si and InP (Fe) substrates by photoreflectance analysisProperties of the interface between the epitaxial layer of heavily doped Al 0.48 In 0.52 As:Si and the InP͑Fe͒ substrate are investigated by photoluminescence in AlInAs:Si/InP͑Fe͒ heteroestructures grown by molecular beam epitaxy. The effect on heterostructure optical properties of including a thin Al 0.22 Ga 0.26 In 0.52 As:Si layer at the interface is investigated as well. To explain the different interface emission energies observed, the results are analyzed by using the mixed-type I-II interface model, which considers in the type II interface a narrow InAs well, with variable width, between AlInAs and InP. The observation of the interface emission at energies as high as 1.36 eV, at low excitation intensity, is explained taking into account the high doping level of the samples. The observed interface transition luminescence thermal quenching is tentatively explained by analyzing the spatial distribution of electrons in the triangular quantum well formed at the type II interface ͑or at the mixed I-II interface͒ as a function of the temperature.