Double-heterostructure GaAs/GaAlAs light-emitting diodes ~LEDs! have been fabricated with the emitter regions beryllium doped to 2310 and 7310 cm. The 7310 cm doped emitters have an internal quantum efficiency of 10% and an optical modulation bandwidth of 1.7 GHz. The steady-state optical output power versus the input current shows an external efficiency of 2.5 mW/mA. The 2310 cm emitters have ...

Scanning tunneling microscopy is used to study low temperature grown (LTG) InGaAs, with and without Be doping. The Be-doped material is observed to contain significantly fewer AsGa antisite defects than the undoped material, with no evidence found for Be-As complexes. Annealing of the LTG-InGaAs forms precipitates preferentially in the undoped material. The previously observed dependence of the...

Impact of illumination on high-mobility dense 2D electron gas in selectively doped single GaAs quantum well with short-period AlAs/GaAs superlattice barriers at T = 4.2 K magnetic fields B < 2 has been studied. It was demonstrated that low temperatures gives rise to enhancement density, mobility and lifetime studied heterostructures. The after for modulated doping had explained as consequenc...

conductivity of the sample and was measured by determining the change in the optical sampling beam polarisation due to a linear electro-optic effect in the cell. The intrinsic time resolution of this experiment is defined by the laser pulse duration. It was however a little worse than 7ps because of the poor impedance matching at the place where the sample was connected into the stripline struc...

The growth of Eu-doped GaN (GaN:Eu) films has been performed on GaAs (100) substrates using RF magnetron sputtering method. The GaN layers exhibit a wurtzite structure. Substrate temperature and the pressure during the deposition do not influence the orientation of GaN:Eu films. After annealing of GaN films in NH3, a strong red luminescence at 622 nm due to Eu ions has been observed.

We show that the spin state of the resident electron in an n-doped self-assembled InAs-GaAs quantum dot can be written and read using nonresonant, circularly polarized optical pumping. A simple theoretical model is presented and accounts for the remarkable dynamics producing counterpolarized photoluminescence.

Coherent potential approximation is used to study the effect of adding doped spherical nanoparticles inside a host matrix on the thermoelectric properties. This takes into account electron multiple scatterings that are important in samples with relatively high volume fraction of nanoparticles (>1%). We show that with large fraction of uniform small size nanoparticles (∼1 nm), the power factor c...

Reflectionless-tunneling was observed in Nb/GaAs superconductor/semiconductor junctions fabricated through a two-step procedure. First, periodic δ-doped layers were grown by molecular beam epitaxy near the GaAs surface, followed by an As cap layer to protect the surface during ex-situ transfer. Second, Nb was deposited by dc-magnetron sputtering onto the GaAs(001) 2× 4 surface in-situ after the...

A reduction of the GaAs surface recombination velocity due to a heavily carbon-doped GaAs ovcrlayer is reported. Metalorganic molecular beam epitaxy using trimethylgallium, triethylgaHium, and elemental arsenic sources has been used to grow an epitaxial structure consisting of 1000 11m of p = 1 X 10 cm-· capped with 10 nm of p = 1 X 10 cm-.l GaAs. Time-resolved photoluminescence (PL) and PL exc...

We report for the first time on the application of generalized ellipsometry at far-infrared wavelengths (wave numbers from 150 cm(-1) to 600 cm(-1)) for measurement of the anisotropic dielectric response of doped polar semiconductors in layered structures within an external magnetic field. Upon determination of normalized Mueller matrix elements and subsequent derivation of the normalized compl...