A. Michon

Direct growth of few-layer graphene on 6H-SiC and 3C-SiC/Si via propane chemical vapor deposition

We propose to grow graphene on SiC by a direct carbon feeding through propane flow in a chemical vapor deposition reactor. X-ray photoemission and low energy electron diffraction show that propane allows to grow few-layer graphene (FLG) on 6H-SiC(0001). Surprisingly, FLG grown on (0001) face presents a rotational disorder similar to that observed for FLG obtained by annealing on (000–1) face. Thanks to a reduced growth temperature with respect to the classical SiC annealing method, we have also grown FLG/3C-SiC/Si(111) in a single growth sequence. This opens the way for large-scale production of graphene-based devices on silicon substrate.

Quantum Hall resistance standards from graphene grown by chemical vapour deposition on silicon carbide

Replacing GaAs by graphene to realize more practical quantum Hall resistance standards (QHRS), accurate to within 10−9 in relative value, but operating at lower magnetic fields than 10 T, is an ongoing goal in metrology. To date, the required accuracy has been reported, only few times, in graphene grown on SiC by Si sublimation, under higher magnetic fields. Here, we report on a graphene device grown by chemical vapour deposition on SiC, which demonstrates such accuracies of the Hall resistance from 10 T up to 19 T at 1.4 K. This is explained by a quantum Hall effect with low dissipation, resulting from strongly localized bulk states at the magnetic length scale, over a wide magnetic field range. Our results show that graphene-based QHRS can replace their GaAs counterparts by operating in as-convenient cryomagnetic conditions, but over an extended magnetic field range. They rely on a promising hybrid and scalable growth method and a fabrication process achieving low-electron-density devices.

Metal organic vapor phase epitaxy of InAsP/InP(001) quantum dots for 1.55μm applications: Growth, structural, and optical properties

This contribution reports the metal organic vapor phase epitaxy of InAsP/InP(001) quantum dots with a voluntary V-alloying obtained owing to an additional phosphine flux during InAs quantum dot growth. The quantum dots were studied by photoluminescence and transmission electron microscopy. We show that the additional phosphine flux allows to tune quantum dot emission around 1.55 μm while improving their optical properties. The comparison of the optical and structural properties of the InAsP quantum dots allows to deduce their phosphorus composition, ranging from 0% to 30% when the phosphine/arsine flow ratio is varying between 0 and 50. On the basis of the compositions deduced, we discuss on the effects of the phosphine flow and of the alloying on the quantum dot growth, structural, and optical properties.

InAs∕InP(001) quantum dots emitting at 1.55μm grown by low-pressure metalorganic vapor-phase epitaxy

In this letter, we report on the structural and optical properties of self-assembled InAs quantum dots (QDs) directly grown on InP(001) by low-pressure metalorganic vapor-phase epitaxy. Transmission electron microscopy reveals defect-free diamond-shaped QDs with a density as high as 2.5×1010cm−2. The QD photoluminescence exhibits an intense peak centered around 1.58μm (785 meV) at room temperature. Changing the growth rate allows one to control the QD density, while maintaining an intense emission centered at this wavelength. These promising results open the way for the realization of efficient InAs∕InP(001) QD-based devices, such as lasers or single-photon sources.

Effects of pressure, temperature, and hydrogen during graphene growth on SiC(0001) using propane-hydrogen chemical vapor deposition

Graphene growth from a propane flow in a hydrogen environment (propane-hydrogen chemical vapor deposition (CVD)) on SiC differentiates from other growth methods in that it offers the possibility to obtain various graphene structures on the Si-face depending on growth conditions. The different structures include the (6√3 × 6√3)-R30° reconstruction of the graphene/SiC interface, which is commonly observed on the Si-face, but also the rotational disorder which is generally observed on the C-face. In this work, growth mechanisms leading to the formation of the different structures are studied and discussed. For that purpose, we have grown graphene on SiC(0001) (Si-face) using propane-hydrogen CVD at various pressure and temperature and studied these samples extensively by means of low energy electron diffraction and atomic force microscopy. Pressure and temperature conditions leading to the formation of the different structures are identified and plotted in a pressure-temperature diagram. This diagram, togeth...

Single InAs1−xPx/InP quantum dots as telecommunications-band photon sources

The optical properties of single InAsP/InP quantum dots are investigated by spectrally-resolved and time-resolved photoluminescence measurements as a function of excitation power. In the short-wavelength region (below 1.45

Experimental observation and analytical model of the stress gradient inversion in 3C-SiC layers on silicon

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Thermal Management for High-Power Single-Frequency Tunable Diode-Pumped VECSEL Emitting in the Near- and Mid-IR

m), the spectra display sharp distinct peaks resulting from the discrete electron-hole states in the dots, while in the long-wavelength range (above 1.45

Time-resolved characterization of InAsP∕InP quantum dots emitting in the C-band telecommunication window

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Microphotoluminescence of exciton and biexciton around 1.5μm from a single InAs∕InP(001) quantum dot

m), these sharp peaks lie on a broad spectral background. In both regions, cascade emission observed by time-resolved photoluminescence confirms that the quantum dots possess discrete exciton and multi-exciton states. Single photon emission is reported for the dots emitting at 1.3