F. Martelli

Institute for Microelectronics and Microsystems

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S. Rubini

Istituto Officina dei Materiali

M. Capizzi

Sapienza University of Rome

A. Polimeni

Sapienza University of Rome

S. Turchini

Institute of Structure of Matter

A. Franciosi

University of Trieste

Giorgio Bais

Elettra-Sincrotrone Trieste S.C.p.A.

Fauzia Jabeen

Fonctions Optiques pour les Technologies de l’information

A. D’Ottavi

Leonardo (United Kingdom)

M. Piccin

Soitec (France)

Rinaldo Trotta

Sapienza University of Rome

Cooperative Institutions

National Research Council

Institute of Structure of Matter

Sapienza University of Rome

Centre National de la Recherche Scientifique

AREA Science Park

Istituto Nazionale per la Fisica della Materia

University of Rome Tor Vergata

National Interuniversity Consortium for the Physical Sciences of Matter

Institute for Microelectronics and Microsystems

National Academies of Sciences, Engineering, and Medicine

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Single photon emitters in dilute nitrides: Towards a determinist approach of quantum dot-photonic crystal nanocavity coupling

Annamaria Gerardino S. Birindelli Johannes S. Wildmann Giorgio Pettinari Luca Businaro

In dilute nitrides [e.g., Ga(AsN), (InGa)(AsN)] the formation of stable N-2H-H complexes following H irradiation removes the effects nitrogen has on the optical (i.e., refractive index [1]), structural [2], and electronic [3] properties of the material. In particular, H binding to N atoms in GaAs 1−x N x leads to an increase in the band gap energy of the N-containing material (∼1.33 eV for x = 1% at T = 5 K) up to the value it has in GaAs (1.52 eV at 5 K). Therefore, by allowing H incorporation only in selected regions of the sample - e.g., by deposition of H-opaque masks prior to the hydrogenation - it is possible to attain a spatially controlled modulation of the band gap energy in the growth plane. This technique, referred to as in-plane Band Gap Engineering, can be employed to tailor the carrier-confining potential down to a nm scale, resulting in the fabrication of site-controlled, dilute nitride-based quantum dots (QDs). We demonstrate here that such QDs emit single photons on demand, as revealed by measuring the second-order correlation function of the single-exciton emission [4].Coupled to the possibility of erasing/rewriting the fabricated patterns through multiple annealing/hydrogenation procedures, the inherently precise control over the position of the nanostructures fabricated with this method renders them naturally suited for the integration with photonic crystal nanocavities.

Blueshift

10.1109/icton.2015.7193631

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Photoluminescence of GaAs nanowires at an energy larger than the zincblende band-gap: dependence on growth parameters

Semiconductor Science and Technology (2015)

F. Martelli Giacomo Priante S. Rubini

In this work we show the possibility of varying the light emission energy from GaAs nanowires within a range of about 40 meV above the zincblende-GaAs band-gap at room temperature and about 50 meV at 100 K. The variable energy emission has been obtained in Au-induced GaAs nanowires grown by molecular beam epitaxy by controlling growth time and V/III flux ratios. We discuss the quantum confinement contribution to the energy differences shown by the different samples and demonstrate that it is negligible. We discuss the obtained results in terms of the existing literature on the band gap of wurtzite GaAs. Our results, combined with those reported in the literature, point out the difficulties of gaining information about bulk properties by investigating nanowires. The achieved control of GaAs NW luminescence energy is able to explain the large spread of data present in the literature; it also opens the way for better understanding and utilization of the electronic properties of GaAs NWs.

Wurtzite crystal structure

10.1088/0268-1242/30/5/055020

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Very high efficiency four-wave mixing in a single semiconductor traveling-wave amplifier

Applied Physics Letters (1996)

A. D’ Ottavi F. Martelli P. Spanò Antonio Mecozzi S. Scotti

We report on high efficiency frequency-conversion obtained by four-wave mixing in a single traveling-wave semiconductor optical amplifier. Efficiency in excess of 0 dB is demonstrated for frequency conversion up to 2 THz. Measurements of the signal to the amplified spontaneous emission background ratio are also presented.

Four-wave mixing

SIGNAL (programming language)

Frequency Conversion

10.1063/1.116007

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InGaAs/GaAs Core–Shell Nanowires Grown by Molecular Beam Epitaxy

IEEE Journal of Selected Topics in Quantum Electronics (2010)

Fauzia Jabeen Vincenzo Grillo F. Martelli S. Rubini

Au-catalyzed In x Ga _1- x As nanowires (NWs) and In x Ga _1- x As/GaAs core-shell NWs were grown by molecular beam epitaxy on (1 1 1)B GaAs. The effects of In content, growth temperature, and V/III elemental flux ratios on NW morphology have been investigated. The structure of the NWs has been characterized by SEM and transmission electron microscopy and their optical properties by low-temperature photoluminescence.

10.1109/jstqe.2010.2068279

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Citations (19)

In-Plane Band Gap Engineering by Hydrogenation of Dilute Nitride Semiconductors

AIP conference proceedings (2007)

Marco Felici A. Polimeni Francesco Masia Rinaldo Trotta Giorgio Pettinari

We present two different methods to pattern the band gap of dilute nitrides in their growth plane by exploiting the unique capability of H to passivate N in these materials. By deposition of metallic masks on and subsequent H irradiation of GaAs1−xNx, we artificially create zones of the crystal having the band gap of untreated GaAs1−xNx well surrounded by GaAs‐like barriers. Alternatively, by focusing an energetic e−‐beam on the surface of hydrogenated GaAs1−xNx we displace H atoms from their N passivation sites, thus leading to a controlled decrease in the crystal band gap in the spatial region where the e−‐beam is steered.

Passivation

Wide-bandgap semiconductor

Crystal (programming language)

Deposition

10.1063/1.2729755

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Optical study of hydrogen-irradiated GaAsN/GaAs heterostructures

Journal of Applied Physics (2011)

M. Geddo M. Patrini G. Guizzetti Mattéo Galli Rinaldo Trotta

The effect of hydrogen irradiation on the optical properties of GaAs1−xNx/GaAs heterostructures was investigated using photoreflectance and reflectance techniques. Systematic measurements performed on both as-grown and hydrogenated samples for N-concentrations ranging from 0.0% to 3.5% and for H-implanted doses from 3 × 1018 to 6 × 1018 ions/cm2 have shown that (a) the H-induced widening of the energy gap is accompanied by a decrease of the refractive index of the H-treated samples with respect to the as-grown ones, resulting in an index mismatch that can be as large as 2% in the subgap spectral region; and (b) the presence of compressive strain in fully passivated GaAsN determines a decrease of the refractive index even below that of GaAs that can be eliminated via moderate thermal annealing. These findings are promising for the development of heterostructures with planar geometry, in which the simultaneous confinement of both carriers and photons, even on a nanometric scale, can be obtained in a single step process.

10.1063/1.3597818

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Structural and optical properties of porous silicon at different porosities

Journal of Applied Physics (1994)

Girolamo Di Francia S. Turchini T. Prosperi F. Martelli Giampiero Amato

In this article we report on the Si atomic environment, investigated by near edge x-ray absorption fine structure (NEXAFS) measurements, and on the optical properties of porous silicon samples having different porosity values (30%, 60%, 80%), the sample with the lowest porosity not being luminescent. On the high porosity samples, time resolved photoluminescence measurements have been performed as a function of the temperature in the 10 K≤T≤300 K. The comparison between structural and optical properties shows that the NEXAFS measurements are consistent with the appearance of a large number of passivating Si-H groups on the surface of the highest porosity samples.

XANES

Porous Silicon

Absorption edge

10.1063/1.357382

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Noise in wavelength conversion using four-wave mixing in semiconductor optical amplifiers

Applied Physics Letters (1997)

F. Martelli Antonio Mecozzi A. D’Ottavi S. Scotti P. Spanò

We measure the pump power dependence of efficiency and signal-to-background ratio in wavelength conversion using four-wave mixing in semiconductor optical amplifiers, for different lengths of the device. We show that the efficiency for a 1-mm-long amplifier is about 40 dB larger and the signal-to-noise ratio is about 23 dB larger than for a 0.25 mm amplifier. We also show that, unlike the efficiency, for constant ratio between pump- and signal-power, the signal-to-background ratio monotonically increases with the pump power. We show theoretically that this behavior holds for any range of pump-power values.

SIGNAL (programming language)

Four-wave mixing

10.1063/1.118400

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An all optical mapping of the strain field in GaAsN/GaAsN:H wires

Applied Physics Letters (2012)

M. Geddo E. Giulotto M. S. Grandi M. Patrini Rinaldo Trotta

GaAsN/GaAsN:H heterostructures were made by an in-plane selective hydrogen incorporation controlled by H-opaque metallic masks. The strain field and hydrogen distributions in GaAsN micro-sized wires thus obtained have been mapped by an all optical procedure that combines micro-Raman scattering and photoreflectance spectroscopy. The strain field is related to the formation of N-H complexes along the hydrogen diffusion profile with an ensuing expansion of the GaAsN lattice whose patterning generates an anisotropic stress in the sample growth plane. These results highlight a powerful non-invasive tool to simultaneously determine both the H diffusion profile and the related strain field distribution.

Strain (injury)

10.1063/1.4766285

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Symmetry of the H-N-H center in dilute III-N-V alloys determined by vibrational spectroscopy with applied stress

Bulletin of the American Physical Society (2010)

Michael Stavola Lanlin Wen Figen Bekisli W. Beall Fowler Rinaldo Trotta

Center (category theory)

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