National Repository of Grey Literature 5 records found  Search took 0.00 seconds. 
Model of carrier multiplication due to impurity impact ionization in boron-doped diamond
Mortet, Vincent ; Lambert, Nicolas ; Hubík, Pavel ; Soltani, A.
Boron-doped diamond exhibits a characteristic S-shaped I-V curve at room temperature [1] with two electrical conductivity states, i.e., low and high conductivity, at high electric fields (50 – 250 due to the carrier freeze-out and impurity impact ionization avalanche effect. To our knowledge, the carrier multiplication during the change of the conductivity state has not been studied. In this article, we investigate theoretically the effect of acceptor concentration and compensation level on the carrier multiplication coefficient at room temperature to determine the optimal dopants concentration of maximum carrier multiplication. The room temperature hole concentration of boron-doped diamond has been calculated for various acceptor concentration and compensation ratio by solving numerically the charge neutrality equation within the Boltzmann approximation of the Fermi-Dirac statistic.\n
The deposition of germanium nanoparticles on hydrogenated amorphous silicon
Stuchlík, Jiří ; Volodin, V.A. ; Shklyaev, A.A. ; Stuchlíková, The-Ha ; Ledinský, Martin ; Čermák, Jan ; Kupčík, Jaroslav ; Fajgar, Radek ; Mortet, Vincent ; More Chevalier, Joris ; Ashcheulov, Petr ; Purkrt, Adam ; Remeš, Zdeněk
We reveal the mechanism of Ge nanoparticles (NPs) formation on the surface of the hydrogenated amorphous silicon (a-Si:H) deposited by Plasma Enhanced Chemical Vapor Deposition (PECVD) on ITO and a on boron doped nanocrystalline diamond (BDD). The coating of Ge NPs on a-Si:H was performed by molecular beam epitaxy (MBE) at temperatures up to 450 °C. The Ge NPs were characterized by Raman spectroscopy, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). The nanocrystalline Ge particles are conglomerates of nanocrystals of size 10-15 nm and quantum dots (QDs) with size below 2 nm embedded in amorphous Ge phase. After coating with Ge NPs the a-Si:H thin films show better adhesion on BDD substrates then on ITO substrates.
(100) substrate processing optimization for fabrication of smooth boron doped epitaxial diamond layer by PE CVD
Mortet, Vincent ; Fekete, Ladislav ; Ashcheulov, Petr ; Taylor, Andrew ; Hubík, Pavel ; Trémouilles, D. ; Bedel-Pereira, E.
Boron doped diamond layers were grown in an SEKI AX5010 microwave plasma enhanced chemical vapour deposition system. Effect of surface preparation, i.e. polishing and O2/H2 plasma etching on epitaxial growth on type Ib (100) HPHT synthetic diamonds were investigated. Using optimized substrate preparation, smooth (RRMS ~ 1 nm) boron doped diamond layers with metallic conduction and free of un-epitaxial crystallites were grown with a relatively high growth rate of 3.7 μm/h. Diamond were characterized by optical microscopy, optical profilometry, atomic force microscopy and Hall effect.
Fabrication methods of diamond coated Love wave SAW biosensors for bacterial detection applications
Drbohlavová, L. ; Bulíř, J. ; Valeš, Václav ; Jákl Křečmarová, M. ; Taylor, Andrew ; Talbi, A. ; Soltani, A. ; Mortet, Vincent
Pathogen detection has a huge importance in the food industry and it can play significant role in the medical practice. This paper focus on the fabrication methods of diamond coated Love wave surface acoustic wave (LW-SAW) biosensors for bacteria detection. LW-SAW sensors have been fabricated on AT-quartz crystals. Interdigitated transducers have been patterned by RF sputtering and photolithography techniques. Amorphous silicon oxide (SiO2) guiding layer and nano-crystalline diamond layer were both deposited by plasma enhanced chemical vapor deposition at low temperature. Preliminary experimental study of diamond surface termination for sensors bio-functionalization is also reported.
Production of nitrogen vacancy centers in nanocrystalline diamond thin film for quantum biosensing applications
Jakl Krečmarová, Marie ; Gulka, Michal ; Fekete, Ladislav ; Remeš, Zdeněk ; Petráková, Vladimíra ; Mortet, Vincent ; Nesládek, M.
Due to its excellent properties such as chemical stability and biocompatibility, diamond is an ideal material for bio sensing application. In particular, nitrogen vacancy (NV) centres in diamond are promising candidates for optical bio-sensing application in nanodiamond particles and single crystal diamond by irradiation (electron, proton, neutron, particles) followed by annealing has been recently developer. Production of NV centres in CVD diamond thin film is important for fabrication of new bio sensor.

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