Temperature dependence of optical transitions in AlGaAs

AlGaAs structures with different aluminum concentration (x = 0.0, 0.17, 0.30, and 0.40) were characterized by photoluminescence and photoreflectance techniques. The temperature dependence of optical transitions in the temperature ranging from 2 to 300 K were investigated. Y. P. Varshni [Physica (Utrecht) 34, 194 (1967)], L. Vina [Phys. Rev. B 30, 1979 (1984)], and R. Passler [Phys. Status Solidi B 200, 155 (1997)] models were used to fit the experimental points. The Passler model gave the best adjustment to the experimental points. The tree models showed that the empirical parameters obtained through the adjustment of the experimental data in the three different models are aluminum composition dependent in the ternary alloy. (C) 2001 American Institute of Physics.891116159616

Electrical and optical characteristics of a Si-doped (Al)GaInAs digital alloy/AlInAs-distributed Bragg mirrors on InP

We report electrical and optical characteristics of a Si-doped (Al)GaInAs digital alloy/AlInAs Bragg mirror lattice matched to InP grown by molecular beam epitaxy, A 98.2% reflectivity with a 107 nm stop band width centred at 1.54 mu m is obtained. An average voltage drop of 16 mV per period at a current density of 1 KA cm(-2) is observed for a mean electron concentration of about 5.5 x 10(18) cm(-3). The influence of structural and intrinsic properties of the heterostructure on the electrical resistivity and optical reflectivity is analysed. (C) 2000 Academic Press.281293

Influence of Al content on temperature dependence of excitonic transitions in quantum wells

AlxGa1-xAs/GaAs double quantum well structures with different well thickness and different barrier aluminum concentration (x = 0.17, 0.30, 0.40) were characterized by the photoluminescence technique. The temperature dependence of excitonic transitions in the temperature range of 2 K to 300 It were investigated, The photoluminescence data obtained give clear evidence of the influence of the aluminum concentration on the temperature dependence of excitonic transitions in the quantum wells. Varshni [Physica (Utrecht) 34, 194 (1967)], Vina et al. [Phys. Rev. B 30, 1979 (1984)] and Passler [Phys. Stab. Sol. (b) 200, 155 (1997)] models were used to fit the experimental points.211111

HOT-ELECTRONS IN DELTA-DOPED GAAS(SI) LAYERS

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Effect of temperature on the optical properties of GaAsSbN/GaAs single quantum wells grown by molecular-beam epitaxy

GaAsSbN/GaAs strained-layer single quantum wells grown on a GaAs substrate by molecular-beam epitaxy with different N concentrations were studied using the photoluminescence (PL) technique in the temperature range from 9 to 296 K. A strong redshift in optical transition energies induced by a small increase in N concentration has been observed in the PL spectra. This effect can be explained by the interaction between a narrow resonant band formed by the N-localized states and the conduction band of the host semiconductor. Excitonic transitions in the quantum wells show a successive red/blue/redshift with increasing temperature in the 2-100 K range. The activation energies of nonradiative channels responsible for a strong thermal quenching are deduced from an Arrhenius plot of the integrated PL intensity. (C) 2003 American Institute of Physics

BROADENING OF THE SI DOPING LAYER IN PLANAR-DOPED GAAS IN THE LIMIT OF HIGH-CONCENTRATIONS

A series of samples of GaAs planar doped with Si, grown by MBE at low substrate temperatures and with different doping concentrations, is investigated. A comparison of Shubnikov-de Haas measurements and self-consistent numerical calculations shows that a broadening of the doped region occurs in spite of the low growth temperature. The broadening occurs via segregation of the Si impurities with the growth surface when the solid solubility limit of Si in GaAs is exceeded. For the growth conditions used this limit is determined to be (2.1 +/- 0.2) x 10(19) cm-3. At high doping densities an intrinsic compensation mechanism becomes active, limiting the concentration of conduction electrons.78979379

Band-edge modifications due to photogenerated carriers in single p-type delta-doped GaAs layers

The photogenerated carrier-induced band-edge modifications of beryllium single delta-doped GaAs layers com comprising a two-dimensional hole gas (2DHG) were investigated by means of photoluminescence, selective photoluminescence, and photoluminescence excitation spectroscopies. The results show direct evidence for a photoinduced electron confinement effect, which strongly enhances the radiative-recombination probability between electrons and holes of the 2DHG at low temperatures,5974634463