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Examines photoluminescence in strained InGaAs-gallium arsenide single heterostructures grown by molecular beam epitaxy. Determination of the critical layer thickness for a range of indium mole fractions; Photoluminescence line shapes for layer thicknesses below and above the critical thickness; Shift of photoluminescence peak energy as a function of layer thickness.

The critical thickness hc of strained InxGa1-xAs layers grown by molecular beam epitaxy on GaAs(100) substrates is determined by double-crystal x-ray diffraction for 0.07≤x≤0.25. The experimental results are in good agreement with critical thicknesses calculated from the energy balance model of R. People and J. C. Bean [Appl. Phys. Lett. 47, 322 (1985)] but differ from prior photoluminescence measurements of hc for this material. Beyond the critical thickness the transition from the strained to the relaxed state occurs more rapidly as the In concentration and hence the lattice mismatch increases. [ABSTRACT FROM AUTHOR]

Variation in the magnitude and sign of the strain in GaAs/InGaAs/GaAs single quantum wells are studied as a function of layer thickness using photoluminescence spectroscopy. It is found that as the compressively strained ternary layer relaxes with increasing thickness, a tensile strain is introduced in the GaAs capping layer. This reduces the GaAs band gap and lifts the degeneracy of the valence band, which becomes light hole in character. [ABSTRACT FROM AUTHOR]