Publications by Martin Heiss | EPFL Graph Search

Related publications (35)

Exciton localization mechanisms in wurtzite/zinc-blende GaAs nanowires

Anna Fontcuberta i Morral, Martin Heiss, Sonia Conesa Boj, Emanuele Uccelli

We investigate the emission properties of excitons in GaAs nanowires containing quantum disks formed by structural alternation between the zinc-blende and wurtzite phases, by means of temperature-dependent photoluminescence. At 10 K the emission from an en ...

American Physical Society (APS)2013

Photonic-Plasmonic Coupling of GaAs Single Nanowires to Optical Nanoantennas

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

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

III-V nanowire arrays: growth and light interaction

Anna Fontcuberta i Morral, Gözde Tütüncüoglu, Martin Heiss, Federico Matteini, Eleonora Russo, Sonia Conesa Boj, Esther Alarcon Llado, Anna Dalmau Mallorquí

Semiconductor nanowire arrays are reproducible and rational platforms for the realization of high performing designs of light emitting diodes and photovoltaic devices. In this paper we present an overview of the growth challenges of III-V nanowire arrays o ...

Institute of Physics2014

Impact of surfaces on the optical properties of GaAs nanowires

Anna Fontcuberta i Morral, Martin Heiss

The effect of surfaces on the optical properties of GaAs nanowires is evidenced by comparing nanowires with or without an AlGaAs capping shell as a function of the diameter. We find that the optical properties of unpassivated nanowires are governed by Ferm ...

American Institute of Physics2010

Determination of the band gap and the split-off band in wurtzite GaAs using Raman and photoluminescence excitation spectroscopy

Anna Fontcuberta i Morral, Martin Heiss, Bernt Ketterer

GaAs nanowires with 100% wurtzite structure are synthesized by the vapor-liquid-solid method in a molecular beam epitaxy system, using gold as a catalyst. We use resonant Raman spectroscopy and photoluminescence to determine the position of the crystal-fie ...

2011

Electrical transport in C-doped GaAs nanowires: surface effects

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

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

Enhancement of Second Harmonic Signal in Nanofabricated Cones

Anna Fontcuberta i Morral, Aleksandra Radenovic, Martin Heiss, Andrea Lovera, Oriol López Sánchez, Fabrizia Dutto

Geometrical effects in optical nanostructures on nanoscale can lead to interesting phenomena such as inhibition of spontaneous emission,(1,2) high-reflecting omnidirectional mirrors, structures that exhibit low-loss-waveguiding,(3) and light confinement.(4 ...

2013

Single crystalline and core-shell indium-catalyzed germanium nanowires-a systematic thermal CVD growth study

Anna Fontcuberta i Morral, Martin Heiss, Sonia Conesa Boj

Germanium nanowires were synthesized using thermal chemical vapor deposition (CVD) and indium as a catalyst. The process parameter space for successful growth was studied. By optimizing the growth temperature and gas pressure, high aspect ratio germanium n ...

Institute of Physics2009

Fundamental limits in the external quantum efficiency of single nanowire solar cells

Anna Fontcuberta i Morral, Martin Heiss

The fundamental limits for the measurement of the efficiency of single nanowire solar cell devices are presented. We evaluate the effect of the substrate, light polarization, and existence of Mie resonances in the absorption of the solar spectrum for nanow ...

American Institute of Physics2011

Gallium arsenide p-i-n radial structures for photovoltaic applications

Michael Graetzel, Anna Fontcuberta i Morral, Martin Heiss, Carlo Colombo

Gallium arsenide p-i-n radial junctions were fabricated by molecular beam epitaxy. The current-voltage characteristics of single nanowires were measured in the dark and under various illumination conditions including 1.5 AM. The total efficiency was 4.5%. ...

American Institute of Physics2009

Tuning the g-factor of neutral and charged excitons confined to self-assembled (Al,Ga)As shell quantum dots

Anna Fontcuberta i Morral, Martin Heiss, Eleonora Russo, Pierre Michel Corfdir, Yannik Fontana

We study the neutral exciton (X) and charged exciton (CX) transitions from (Al,Ga) As shell quantum dots located in core-shell nanowires, in the presence of a magnetic field. The g-factors and the diamagnetic coefficients of both the X and the CX depend on ...

American Institute of Physics2014

Self-assembled quantum dots in a nanowire system for quantum photonics

Nicola Marzari, Anna Fontcuberta i Morral, Marco Cantoni, Martin Heiss, Eleonora Russo, Sonia Conesa Boj, Yannik Fontana, Bernt Ketterer

Quantum dots embedded within nanowires represent one of the most promising technologies for applications in quantum photonics. Whereas the top-down fabrication of such structures remains a technological challenge, their bottom-up fabrication through self-a ...

Nature Publishing Group2013

In(Ga)As quantum dot formation on group-III assisted catalyst-free InGaAs nanowires

Anna Fontcuberta i Morral, Martin Heiss, Emanuele Uccelli, Bernt Ketterer

Growth of GaAs and InxGa1-xAs nanowires by the group-III assisted molecular beam epitaxy growth method on (001)GaAs/SiO2 substrates is studied in dependence on growth temperature, with the objective of maximizing the indium incorporation. Nanowire growth w ...

Institute of Physics2011

Plastic and Elastic Strain Fields in GaAs/Si Core-Shell Nanowires

Christophe Ballif, Anna Fontcuberta i Morral, Martin Heiss, Sylvain Dunand, Eleonora Russo, Sonia Conesa Boj

Thanks to their unique morphology, nanowires have enabled integration of materials in a way that was not possible before with thin film technology. In turn, this opens new avenues for applications in the areas of energy harvesting, electronics, and optoele ...

American Chemical Society2014

Growth mechanisms and process window for InAs V-shaped nanoscale membranes on Si[001]

Anna Fontcuberta i Morral, Gözde Tütüncüoglu, Martin Heiss, Eleonora Russo, Sonia Conesa Boj, Esther Alarcon Llado, Anna Dalmau Mallorquí

Organized growth of high aspect-ratio nanostructures such as membranes is interesting for opto-electronic and energy harvesting applications. Recently, we reported a new form of InAs nano-membranes grown on Si substrates with enhanced light scattering prop ...

Institute of Physics2013

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

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

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

Single-nanowire solar cells beyond the Shockley-Queisser limit

Anna Fontcuberta i Morral, Martin Heiss

Light management is of great importance in photovoltaic cells, as it determines the fraction of incident light entering the device. An optimal p-n junction combined with optimal light absorption can lead to a solar cell efficiency above the Shockley-Queiss ...

Nature Publishing Group2013

Catalyst-free nanowires with axial InxGa1-xAs/GaAs heterostructures

Anna Fontcuberta i Morral, Martin Heiss, Sonia Conesa Boj

Self-catalyzed growth of axial InxGa1-xAs/GaAs heterostructures has been realized by molecular beam epitaxy. The growth of the wires is achieved from gallium/indium alloy droplets that are nucleated in situ. By variation of the In/Ga beam flux during the g ...

Institute of Physics2009

Hybrid axial and radial Si-GaAs heterostructures in nanowires

Christophe Ballif, Anna Fontcuberta i Morral, Martin Heiss, Sylvain Dunand, Eleonora Russo, Sonia Conesa Boj, Daniel Rüffer

Hybrid structures are formed from materials of different families. Traditionally, group IV and III-V semiconductors have not been integrated together in the same device or application. In this work we present a new approach for obtaining Si-GaAs hybrid het ...

Royal Society of Chemistry2013

Spatially resolved Raman spectroscopy on indium-catalyzed core-shell germanium nanowires: size effects

Anna Fontcuberta i Morral, Martin Heiss

The structure of indium-catalyzed germanium nanowires is investigated by atomic force microscopy, scanning confocal Raman spectroscopy and transmission electron microscopy. The nanowires are formed by a crystalline core and an amorphous shell. We find that ...

Institute of Physics2010