Journal of Vacuum Science & Technology B Microelectronics Processing and Phenomena · 1989 · 18 citations · 0 references
Natural SciencesMaterials SciencePhysicsCondensed Matter PhysicsOptoelectronicsSemiconductor MaterialsElectron-phonon InteractionsElectronic Band StructureOptical Properties Of SemiconductorsOptical Properties Of SolidsSemiconductor PhysicsTwo-dimensional SemiconductorsCarrier-phonon CouplingConduction BandExciton-phonon CouplingHydrostatic PressureIndirect Band GapPhotoluminescencePhotoluminescence SpectroscopyStokes Shift
A photoluminescence (PL) and PL excitation (PLE) investigation of GaAs/AlAs superlattices near the direct to indirect gap, type I to type II superlattice crossover is reported. The nature of the phonon coupling, the magnitude of the Stokes’ shifts between PL and PLE, and the dependence of the PL spectra on hydrostatic pressure are studied. From these results a change of the GaAs width (d) by just 1 monolayer (ML) from 12 to 11 ML is shown to cover the range from near coincidence of the GaAs (Γ) and AlAs (X) conduction band minima, but with type I, direct gap character dominant at d=12 ML, to clearly indirect gap, type II behavior at d=11 ML.