Publications de Alberto Casadei

Investigations of doping via optical pump terahertz-probe spectroscopy

Anna Fontcuberta i Morral, Alberto Casadei, Federico Matteini, Francesca Amaduzzi

Reliable doping in semiconductor nanowires is essential for the development of novel optoelectronic devices. Dopant incorporation within the nanowire can allow for optimisation of key optoelectronic properties, such as electron mobility and carrier lifetim ...

IEEE Computer Societyhelp@computer.org2017

GaAs nanowires: from doping to plasmonic hybrid devices

Alberto Casadei

Semiconductor nanowires (NWs) are filamentary crystals with the diameter ranging from few tens up to few hundreds of nanometers. In the last 20 years, they have been intensively studied for the prospects that their unique quasi-one dimensional shape offers ...

EPFL2016

Increased Photoconductivity Lifetime in GaAs Nanowires by Controlled n-Type and p-Type Doping

Anna Fontcuberta i Morral, Alberto Casadei, Federico Matteini, Fauzia Jabeen

Controlled doping of GaAs nanowires is crucial for the development of nanowire-based electronic and optoelectronic devices. Here, we present a noncontact method based on time resolved terahertz photoconductivity for assessing n- and p-type doping efficienc ...

American Chemical Society2016

Modulation Doping of GaAs/AlGaAs Core-Shell Nanowires With Effective Defect Passivation and High Electron Mobility

Anna Fontcuberta i Morral, Sonia Conesa Boj, Alberto Casadei, Federico Matteini, Fauzia Jabeen, Francesca Amaduzzi

Reliable doping is required to realize many devices based on semiconductor nanowires. Group IIIV nanowires show great promise as elements of high-speed optoelectronic devices, but for such applications it is important that the electron mobility is not comp ...

American Chemical Society2015

Terahertz spectroscopy of modulation doped core-shell GaAs/AlGaAs nanowires

Anna Fontcuberta i Morral, Daniel Rüffer, Sonia Conesa Boj, Alberto Casadei, Federico Matteini, Francesca Amaduzzi

In order to realize many devices based on semiconductor nanowires, reliable doping is essential. For such devices, it is important that the electron mobility is not compromised by doping incorporation. Here, we show that core-shell GaAs/AlGaAs nanowires ca ...

IEEE2015

Hybrid Semiconductor Nanowire-Metallic Yagi-Uda Antennas

Anna Fontcuberta i Morral, Gözde Tütüncüoglu, Alberto Casadei, Federico Matteini, Mohammad Ramezani

We demonstrate the directional emission of individual GaAs nanowires by coupling this emission to Yagi-Uda optical antennas. In particular, we have replaced the resonant metallic feed element of the nanoantenna by an individual nanowire and measured with t ...

American Chemical Society2015

Polarization response of nanowires a la carte

Anna Fontcuberta i Morral, Martin Heiss, Esther Alarcon Llado, Eleonora Russo, Alberto Casadei, Francesca Amaduzzi

Thanks to their special interaction with light, semiconductor nanowires have opened new avenues in photonics, quantum optics and solar energy harvesting. One of the major challenges for their full technological deployment has been their strong polarization ...

Nature Publishing Group2015

Photonic-Plasmonic Coupling of GaAs Single Nanowires to Optical Nanoantennas

Anna Fontcuberta i Morral, Martin Heiss, Gözde Tütüncüoglu, Eleonora Russo, Alberto Casadei, Federico Matteini

We successfully demonstrate the plasmonic coupling between metal nanoantennas and individual GaAs nanowires (NWs). In particular, by using dark-field scattering and second harmonic excitation spectroscopy in partnership with analytical and full-vector FDTD ...

American Chemical Society2014

Electrical transport in C-doped GaAs nanowires: surface effects

Anna Fontcuberta i Morral, Martin Heiss, Esther Alarcon Llado, Eleonora Russo, Alberto Casadei, Fauzia Jabeen, Jil Schwender, Mohammad Ramezani

The resistivity and mobility of carbon-doped GaAs nanowires have been studied for different doping concentrations. Surface effects have been evaluated by comparing unpassivated with passivated nanowires. We directly see the influence of the surface: the pi ...

Wiley-Blackwell2013

Doping incorporation paths in catalyst-free Be-doped GaAs nanowires

Anna Fontcuberta i Morral, Carlo Colombo, Martin Heiss, Alberto Casadei

The incorporation paths of Be in GaAs nanowires grown by the Ga-assisted method in molecular beam epitaxy have been investigated by electrical measurements of nanowires with different doping profiles. We find that Be atoms incorporate preferentially via th ...

American Institute of Physics2013