We have studied doped superlattices of GaAs/AlGaAs composition. When the doping atoms are introduced into the barriers surrounding the superlattice, as well as to the inner ones, but with half of the concentration, the photoluminescence due to interband transitions from extended superlattice states is detected. This is demonstrated by a study of the sample’s photoluminescence in a magnetic fiel...

The Fröhlich interaction is one of the main electron-phonon intrinsic interactions in polar materials originating from the coupling of one itinerant electron with the macroscopic electric field generated by any longitudinal optical (LO) phonon. Infrared magnetoabsorption measurements of doped GaAs quantum well structures have been carried out in order to test the concept of Fröhlich interaction...

The study of the electronic structure in GaAs-based delta-doped field effect transistors under applied hydrostatic pressure is presented. A combination of the depletion approximation and the local density Thomas-Fermi theory is used to model the potential energy profile. We present a discussion on the possible effect of the hydrostatic pressure in the formation of high conductivity channels in ...

This investigation experimentally demonstrates the dynamic characteristics of quantum dot vertical-cavity surface-emitting lasers (QD VCSEL) without and with light injection. The QD VCSEL is fully doped structure on GaAs substrate and operates in the 1.3 mum optical communication wavelength. The eye diagram, frequency response, and intermodulation distortion are presented. We also demonstrate t...

The GaAs short-period superlattices have been grown for the first time by the metal-organic hydride epitaxy method using Se and C for quasi-doping. Photoluminescence spectra measured at 4.2 K display well-distinguished peaks, which coincide with transitions between quantizied levels of electrons and holes in the potential relief quantum wells. To describe observed phenomena in quasi-doped super...

We have examined the effects of electron-hole plasma generation on excitonic absorption phenomena in nipi-doped In&&,sAs/GaAs multiple quantum wells (MQWs) using a novel technique called electron beam-induced absorption modulation imaging. The electron-hole plasma is generated by a high-energy electron beam in a scanning electron microscope and is used as a probe to study the MQW absorption mod...

We have performed terahertz time-domain magnetospectroscopy by combining a rapid scanning terahertz time-domain spectrometer based on the electronically controlled optical sampling method with a table-top minicoil pulsed magnet capable of producing magnetic fields up to 30 T. We demonstrate the capability of this system by measuring coherent cyclotron resonance oscillations in a high-mobility t...

Electrons in bulk n-doped GaAs at a lattice temperature of 300 K are driven by ultrashort high-field transients of up to 300 kV/cm in the terahertz frequency range. In the lowest conduction band the carriers show coherent ballistic motion, which is detected via the THz field emitted by them. This partial Bloch oscillation is reproduced by a quantum-kinetic theory of coherent transport on ultraf...

Andreev-reflection dominated transport is demonstrated in Al/nIn0.38Ga0.62As superconductor-semiconductor junctions grown by molecularbeam epitaxy on GaAs(001). High junction transparency was achieved in low-doped devices by exploiting Si interface bilayers to suppress the native Schottky barrier. It is argued that this technique is ideally suited for the fabrication of ballistic transport hybr...

We report the operation of a Bloch oscillator. The active medium was a staticvoltage driven, doped GaAs/AlAs superlattice which was electromagnetically coupled to a resonator. The oscillator produced tuneable microwave radiation (frequency ~ 60 GHz; power ~ 0.5 mW; efficiency ~ 4 %). The gain (~ 10 cm) was due to the nonlinearity mediated by miniband electrons. We also present a theory of the o...