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Abstract: In this work, we have studied the dependence of the size and luminescence of self-assembled InAs quantum dots (SAQDs) on the growth conditions. The SAQDs were grown on GaAs (100) substrates by molecular beam epitaxy (MBE). Their structural and optical properties were studied by atomic force microscopy (AFM), and photoluminescence spectroscopy (PL). The growth of the InAs SAQDs was in situ monitored by reflection high-energy electron diffraction (RHEED). The shape and size of the InAs SAQDs were significantly affected by the growth temperature and the arsenic over-pressure. We observe a decrease of the SAQDS density and an increase in their height by increasing the growth temperature, and/or decreasing the arsenic over-pressure. This is accompanied by a remarkable red-shift of the PL emission energy from 1.3 to . [Copyright &y& Elsevier]

Modulation-doped GaAs/AlGaAs heterostructures have been studied by photoreflectance spectroscopy. The spectra at room temperature show Franz–Keldysh oscillations associated to the substrate–buffer layer interface. The built-in electric field magnitude calculated from these oscillations is related with the two-dimensional electron gas (2DEG) mobility. In addition we observed two signals associated to the GaAs capping layer and to the 2DEG, respectively. [Copyright &y& Elsevier]

Abstract: InAs layers with thickness of monolayer (-layers) were grown by MBE embedded in GaAs barriers in the direction [100]. Photoluminescence (PL) spectroscopy was employed to study the electronic transitions in the -layers. By secondary-ion mass spectroscopy (SIMS) we checked out the possible In segregation. The samples consist of five InAs -layers embedded in between 60nm-thick GaAs barriers, such that the electron wave functions do not overlap each other, as we verified with a model of a square quantum well (SQW), which help us to calculate also the well width. [Copyright &y& Elsevier]