Variable-temperature photoluminescence PL spectra of Si-doped self-assembled InGaAs quantum dots QDs with and without GaAs cap layers were measured. Narrow and strong emission peak at 1075 nm and broad and weak peak at 1310 nm were observed for the buried and surface QDs at low temperature, respectively. As large as 210 meV redshift of the PL peak of the surface QDs with respect to that of the ...

The local density of states of Mn-Mn pairs in GaAs is mapped with cross-sectional scanning tunneling microscopy and compared with theoretical calculations based on envelope-function and tight-binding models. These measurements and calculations show that the crosslike shape of the Mn-acceptor wave function in GaAs persists even at very short Mn-Mn spatial separations. The resilience of the Mn-ac...

Linear ac 888 Hz resistance of highly mobile two-dimensional electrons in GaAs heavily doped quantum wells is studied at different magnitudes of dc and ac 10 KHz to 20 GHz excitations. In the dc excitation regime the differential resistance oscillates with the dc current and external magnetic field similar to that observed earlier in AlGaAs/GaAs heterostructures C. L. Yang et al., Phys. Rev. Le...

A robust long-range antiferromagnetic coupling between ferromagnetic Ga0.97Mn0.03As layers has previously been realized via insertion of nonmagnetic Be-doped GaAs spacers between the magnetic layers. In this paper we report the observation of weak antiferromagnetic coupling between Ga0.97Mn0.03As layers through undoped GaAs spacers with thicknesses as large as 25 monolayers. The field and the t...

In this work, we present a theoretical photoluminescence (PL) for p-doped GaAs/InGaAsN nanostructures arrays. We apply a self-consistent k→p→ method in the framework of the effective mass theory. Solving a full 8 × 8 Kane's Hamiltonian, generalized to treat different materials in conjunction with the Poisson equation, we calculate the optical properties of these systems. The trends in the calcu...

High crystalline quality ZnBeSe epilayers were grown nearly lattice matched to GaAs ~001! substrates by molecular beam epitaxy with a Be–Zn co-irradiation. A ~132! reflection high energy electron diffraction pattern was observed after the Be–Zn co-irradiation of the GaAs ~234! surface. A high p-type doping level of 1.5310 cm was achieved for ~N1Te! triple-delta doping ~d doping! of ZnBeSe epila...

In this work we present studies for the behavior of impurity breakdown of two GaAs samples grown by Molecular Beam Epitaxy at 200oC and 300oC. We vary the temperature and the illumination intensity. For the sample grown at 200oC, the transport mechanism after the breakdown is of the same type of the main free carriers at low electric elds. Below 100K, a clear dependence of the threshold electri...

The demand for fast and temperature stable lasers emitting in the telecom wavelengths drives the research on quantum dot lasers. While low and temperature insensitive threshold current densities are expected, InAs/GaAs quantum dot lasers emitting around 1.3 μm have not yet fulfilled their expectations. From the literature, one can observe that although high temperature stability can be achieved...

We present a quantitative conduction model for nonalloyed ohmic contacts to n-type GaAs ~n:GaAs! which employ a surface layer of low-temperature-grown GaAs ~LTG:GaAs!. The energy band edge profile for the contact structure is calculated by solving Poisson’s equation and invoking Fermi statistics using deep donor band and acceptor state parameters for the LTG:GaAs which are consistent with measu...

The doping and temperature dependence of the complex conductivity is determined for the ferromagnetic semiconductor Ga(1-x)Mn(x)As. A broad resonance develops with Mn doping at an energy scale of approximately 200 meV, well within the GaAs band gap. Possible origins of this feature are explored in the context of a Mn induced impurity band and intervalence band transitions. From a sum rule analy...