An iterative procedure which utilizes the type-1 and type-II transitions of a GaAs/AlAs single quantum well is used to determine the GaAs/AlAs valence-band offset. The iteration is based on the fact that the confinement energy is not sensitive to the change of the barrier potential. It has the advantage that knowledge of the thickness of the quantum well is not necessary to determine the valence-band offset. Both the type-1 and type-II transitions can be observed in the low-temperature photoluminescence spectrum if the GaAs is thin enough so that the lowest-energy level of the electron in the GaAs well is higher than the X-conduction-band minimum of the adjacent AlAs. We illustrate this procedure with a 35 A GaAs/AlAs single quantum well, and the valence-band offset is found to be 36% of the r-gap difference.

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Interband transitions in Cd0.07Zn0.93Te/ZnTe strained single quantum wells grown by doublewell temperature gradient vapor deposition A monolithic seriesconnected Al0.93Ga0.07As/GaAs solar cell array GaAs/In 0.07 Al 0.93 As tensile-strained quantum wells were grown on ͓001͔ GaAs substrates using molecular-beam epitaxy. The incorporation of tensile strain is made possible by preparing a 1-m-thick In 0.07 Al 0.93 As relaxed buffer which is followed by the growth of quantum wells. The strain of the GaAs was measured using Raman spectroscopy and photoluminescence. The photoluminescence measurements from wells ranging in thickness from 25 to 100 Å reveal that the observed optical transition originates from the electron-light hole recombination for a 100 Å well and from the electron-heavy hole recombination if the well thickness is less than 40 Å. Therefore, a thick Al-rich In x Al 1Ϫx As relaxed buffer on the GaAs substrate can be used to engineer the relative energy position of the light and heavy holes for GaAs-based quantum wells.

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