Daniel Turover

NAPA Technologies

Deploying advanced imaging solutions to robotic and autonomous systems by mimicking human vision requires simultaneous acquisition of multiple fields of views, named the peripheral and fovea regions. Among 3D computer vision techniques, LiDAR is currently considered at the industrial level for robotic vision. Notwithstanding the efforts on LiDAR in...

Titanium nitride (TiN) is a very promising new plasmonic material to replace traditional plasmonic materials like gold and silver, especially thanks to its thermal and chemical stability. However, its chemical resistance and its hardness make TiN difficult to microstructure. An alternative approach is to micro-nanostructure a titanium dioxide (TiO...

Deploying advanced imaging solutions to robotic and autonomous systems by mimicking human vision requires simultaneous acquisition of multiple fields of views, named the peripheral and fovea regions. Low-resolution peripheral field provides coarse scene exploration to direct the eye to focus to a highly resolved fovea region for sharp imaging. Amon...

Deploying advanced imaging solutions to robotic and autonomous systems by mimicking human vision requires simultaneous acquisition of multiple fields of views, named the peripheral and fovea regions. Low-resolution peripheral field provides coarse scene exploration to direct the eye to focus to a highly resolved fovea region for sharp imaging. Amon...

Scintillators play a key role in the detection chain of several applications which rely on the use of ionizing radiation, and it is often mandatory to extract and detect the generated scintillation light as efficiently as possible. Typical inorganic scintillators do however feature a high index of refraction, which impacts light extraction efficien...

Scintillators play a key role in the detection chain of several applications which rely on the use of ionizing radiation, and it is often mandatory to extract and detect the generated scintillation light as efficiently as possible. In positron emission tomography (PET), for example, both energy resolution and coincidence resolving time, two of the...

It is shown that substrate pixelisation before epitaxial growth can significantly impact the emission color of semiconductor heterostructures. The wavelength emission from InxGa1−xN/GaN quantum wells can be shifted from blue to yellow simply by reducing the mesa size from 90 × 90 µm2 to 10 × 10 µm2 of the patterned silicon used as the substrate. Th...

Living organisms have developed many strategies to produce colors and to modify appearance. Even if the use of pigments is widely spread, the effects produced by micro/nano patterning allow a larger range of possibilities. Indeed, the structuration of materials on multiple levels combined with intrinsic material properties offer a wide range of vis...

The improvement of the energy and of the timing resolution is always a challenge in scintillation-based detectors. A large fraction of the photons produced by scintillation remains trapped inside the crystal. Photonic crystals have been suggested as a solution to improve light extraction. Here we will present results obtained with a nanostructured...

Scintillating crystals are used in numerous applications of ionizing radiation detectors. In time of flight positron emission tomography (TOF-PET) for example, both energy- and coincidence time resolution (CTR) are important characteristics that could significantly benefit if more light from scintillators, otherwise trapped, could be collected by t...

This paper presents a new alternative fabrication of biochemical sensor based on surface enhanced Raman scattering (SERS) by soft nanoimprint lithography (S-NIL) on SiO2 sol-gel. Stabilization of the sol-gel film is obtained by annealing which simplifies the manufacturing of these biosensors and is compatible with mass production at low cost. This...

La présente invention concerne un insert (6) pour moule d'injection destiné à la fabrication de pièces en matériau polymérique se caractérisant en ce qu'il comprend : - une première partie (9) réalisée en une résine, ladite première partie comportant une surface de moulage (20) qui comprend au moins un motif de texturation ; - une deuxième partie (...

In order to demonstrate the benefits of photonic crystals for PET imaging, the partners of the Turbo-PET project are committed to the development of a new high-resolution, high-sensitivity nuclear imaging breast PET system. CERN and UTT develop and simulate light extracting photonic solutions. NAPA patterns the LYSO scintillating crystals blocks (T...

Developed in partnership with SILSEF and AII Companies R&D teams, the described test bench offers a solution for dynamic liquid adhesion measurements on a wide range of materials. SILSEF develops and produce functional micro and nano-patterns on the industrial scale on a wide range of materials (glass, metal, polymers, semiconductors, thin films, …...

Our aim was to elaborate a novel method for fully controllable large-scale nanopatterning. We investigated the influence of the surface topology, i.e., a pre-pattern of hydrogen silsesquioxane (HSQ) posts, on the self-organization of polystyrene beads (PS) dispersed over a large surface. Depending on the post size and spacing, long-range ordering o...

2cm diameter hydrothermal ZnO crystals were grown and then made into substrates using both mechanical and chemical-mechanical polishing (CMP). CMP polishing showed superior results with an (0002) Ω scan full width half maximum (FWHM) of 67arcsec and an root mean square (RMS) roughness of 2Å. In comparison, commercial melt-grown substrates exhibited...

The interaction of Co thin films on atomically flat ZnO(000–1) has been investigated by low energy electron diffraction (LEED), scanning tunneling microscopy (STM) and Auger electron spectroscopy (AES). A high density of islands nucleates at the earliest stages of the growth and a subsequent Wolmer–Weber growth of these islands is observed. Upon an...

The effect of annealing of Co/ZnO(0001) was studied by scanning tunneling microscopy, low energy electron diffraction, and Auger electron spectroscopy. At room temperature, Co forms islands on ZnO. Annealing up to 940 K leads to coalescence of the islands. At 970 K, Co diffuses into ZnO where it partially replaces Zn. A model of the Auger intensiti...

In this study, we established a cleaning procedure to obtain atomically flat (000-1) surfaces from pressurized melt grown ZnO. Ex situ chemical cleaning removes fluid layer and trapped contaminants from the surface. This was followed by cycles of sputtering and annealing in ultrahigh vacuum. It is critical that the ion energy be high enough to prod...

In this paper, we report new results on polishing and characterization of thick aluminium nitride (AlN) layers grown on 2- and 3-inch electrically conducting 4H-SiC on-axis substrate. As thick as 10-22 µm AlN layers were deposited on Si-face by stress control hydride vapor phase epitaxy. Rough as-grown layers were polished to provide epi-ready surf...

We established a cleaning procedure to obtain atomically flat surfaces from pressurized melt grown ZnO using ex-situ and in-situ processing. The ex-situ chemical cleaning consisted in removing the surface fluid layer and contaminants from the surface. The physical in-situ procedure used sputtering-annealing cycles to clean and reconstruct the surfa...

Unlike other techniques for surface cleaning/etching such as dry etching (RIE, ICP), the new polishing process does not degrade Schottky diode forward characteristics. Thus, apart from the promising improvement of starting material quality, fine surface polishing seems to offer significant advantages in terms of increasing manufacturing yield.

In this work, we have investigated the 3C-SiC re-growth on planarized 3C-SiC epitaxial layers, grown on (001)Si, after the application of a chemical mechanical polishing (CMP) process. A specific polishing process was developed for 3C-SiC to achieve a flat, high-quality surface. The interface between the deposited 3C-SiC and the polished 3C-SiC on...

The excellent chemical and mechanical properties of SiC make, paradoxically, damage free surface preparation a real challenge. The preparation of SiC wafers can be described in four successive stages corresponding to different objectives: —Grinding/lapping gives good geometrical parameters to the wafer. —Mechanical polishing enables a decrease in...

Surface treatment is a key technological parameter in the microelectronics technology and especially for SiC devices since high temperatures must be used for implanted impurities annealing and crystal damage recovery. In this work we take profit of a novel fine polishing process developed by NOVASIC to improve the electrical characteristics of Boro...