Wavelength control from 1.25 to 1.4 um in InxGa1-xAs quantum dot structures grown by metal organic chemical vapor deposition.

Times cited: 47 2005 Journal Impact Factor: 4.12

Multicolor oligothiophene-based LEDs

We demonstrate wide tunability, from green to near infrared, of the electroluminescence emission of substituted oligothiophene compounds. The compounds are characterized by high chemical stability, electron affinities up to 3.1 eV and photoluminescence efficiencies up to 70%. These characteristics make these materials excellent candidates for application in light-emitting diodes. We obtain low turn-on voltage devices with electroluminescence efficiency up to 0.2%, more than one order of magnitude larger than the values reported for unsubstituted oligothiophene compounds

Nano-island fabrication by electron beam lithography and selective oxidation ofAl-rich AlGaAs layers for single electron device application

A nanometer-scale island embedded between two tunnel junctions constitutes the elementary cell of single electron devices (SED), such as single electron transistors (SET) and memories. In this work we report on a new method for the fabrication of a nanometer-scale semiconductor island through AlGaAs/GaAs epitaxial growth, electron beam lithography and selective oxidation of Al-rich AlGaAs layers. We have used a combination of high-resolution electron beam lithography and selective oxidation of Al-rich AlGaAs layers in order to fabricate a non-oxidized semiconductor island smaller than the electron beam lithography (EBL) defined size. The pattern was transferred down to the bottom AlAs layer and a selective oxidation of the Al-rich layers was performed in water vapor at a temperature of 300 °C, which led to the formation of the aluminum oxide. The higher oxidation rate of the AlAs compared to the Al0.8Ga0.2As layer, together with the strain accumulation in the Al0.8Ga0.2As, caused the formation of nanoscale semiconductor islands embedded in an aluminum oxide shell. After the oxidation and cleavage of the sample, selective wet etching has been performed in order to evidence the unoxidized region through an SEM inspection

Multicolor oligothiophene-based LEDs

We demonstrate wide tunability, from green to near infrared, of the electroluminescence emission of substituted oligothiophene compounds. The compounds are characterized by high chemical stability, electron affinities up to 3.1 eV and photoluminescence efficiencies up to 70%. These characteristics make these materials excellent candidates for application in light-emitting diodes. We obtain low turn-on voltage devices with electroluminescence efficiency up to 0.2%, more than one order of magnitude larger than the values reported for unsubstituted oligothiophene compounds

Dependence of the emission wavelength on the internal electric field in quantum dot laser structures grown by metal-organic chemical-vapor deposition.

Times cited: 17 2005 Journal Impact Factor: 4.12

Time Resolved Magneto-Optical properties of InxGa(1-x)As V-shaped single Quantum Wires

In this work we present a time-resolved magneto-luminescence investigation (up to 8 T) of InGaAs V-shaped quantum wires (QWRs) with different In content, as a function of temperature and the applied magnetic field. The states of the wires were investigated by CW PL and quantitatively compared with the results of a numerical solution of the two-dimensional Schrodinger equation. Time-resolved experiments performed in magnetic field at different temperatures indicate the existence of a competition between the electron confinement occurring in deep QWRs at low temperature, and the magnetic confinement prevailing in shallower QWRs