Search results for "Gate"
showing 10 items of 1811 documents
Characterization of soft breakdown in thin oxide NMOSFETs based on the analysis of the substrate current
2001
We have investigated the properties of soft breakdown (SBO) in thin oxide (4.5 nm) nMOSFETs with measurements of the gate and substrate leakage currents using the carrier separation technique. We have observed that, at lower gate voltages, the level of the substrate current exhibits a plateau. We propose that the observed plateau is due to the Shockley-Hall-Read (SHR) generation of hole-electron pairs in the space charge region and at the Si-SiO/sub 2/ interface. At higher voltages, the substrate current steeply increases with voltage, due to a tunneling mechanism, trap-assisted or due to a localized effective thinning of the oxide, from the substrate valence band to the gate conduction ban…
Second-harmonic Generation Microscopy of Carbon Nanotubes
2012
We image an individual single-walled carbon nanotube (SWNT) by second-harmonic generation (SHG) and transmission electron microscopy and propose that SHG microscopy could be used to probe the handedness of chiral SWNTs.
Toward Photopatternable Thin Film Optical Sensors Utilizing Reactive Polyphenylacetylenes
2013
Substituted polyphenylacetylenes featuring reactive pentafluorophenyl (PFP) ester moieties are synthesized. Parts of the reactive PFP groups are then converted with a mono ortho-nitrobenzyl-protected diamine in variable ratios. Thin films are prepared from these copolymers and irradiated with UV light (λ = 365 nm), resulting in crosslinking of the irradiated areas and hence enabling a photopatterning. We found that during the photocrosslinking process, the excess of PFP ester moieties is stable and remained intact, enabling a subsequent post-polymerization modification step with amines. Noteworthy, this subsequent modification with amines results in a dramatically shift in the UV-vis absorp…
Inherently fluorescent polyaniline nanoparticles in a dynamic landscape
2012
Abstract In this paper we report for the first time on the emissive behavior of two polyaniline (PANI) nanoparticle systems produced via oxidative chemical polymerization in the presence of either poly(vinyl alcohol) (PVA) or chitosan as polymeric stabilizers in water. The emission from PANI nanoparticles is irreversibly quenched by an increase of pH of the suspending medium from acid to neutral (chitosan–PANI) or alkaline (PVA–PANI). Conversely, PANI nanorods synthesized in the same conditions of the above, but in presence of poly(N-vinyl pyrrolidone), is not emissive at any pH. The role of the polymeric surfactant as a soft template is key in controlling the morphology and the properties …
Highly soluble multifunctional MnO nanoparticles for simultaneous optical and MRI imaging and cancer treatment using photodynamic therapy
2010
Superparamagnetic MnO nanoparticles were functionalized using a hydrophilic ligand containing protoporphyrin IX as photosensitizer. By virtue of their magnetic properties these nanoparticles may serve as contrast enhancing agents for magnetic resonance imaging (MRI), while the fluorescent target ligand protoporphyrin IX allows simultaneous tumor detection and treatment by photodynamic therapy (PDT). Caki-1 cells were incubated with these nanoparticles. Subsequent exposure to UV light lead to cell apoptosis due to photoactivation of the photosensitizer conjugated to the nanoparticles. This method offers great diagnostic potential for highly proliferative tissues, including tumors. In additio…
Electrochemical Tantalum Oxide for Resistive Switching Memories
2017
Redox-based resistive switching memories (ReRAMs) are strongest candidates for the next-generation nonvolatile memories fulfilling the criteria for fast, energy efficient, and scalable green IT. These types of devices can also be used for selector elements, alternative logic circuits and computing, and memristive and neuromorphic operations. ReRAMs are composed of metal/solid electrolyte/metal junctions in which the solid electrolyte is typically a metal oxide or multilayer oxides structures. Here, this study offers an effective and cheap electrochemical approach to fabricate Ta/Ta2O5-based devices by anodizing. This method allows to grow high-quality and dense oxide thin films onto a metal…
Molecular design of the diketopyrrolopyrrole-based dyes with varied donor units for efficient dye-sensitized solar cells
2014
Abstract Three types of novel diketopyrrolopyrrole-based organic dyes ( Type 1 – 3 ) with phenyl unit as an additional π -bridge and triphenylamine or phenothiazine as the donors are designed and synthesized for dye-sensitized solar cells (DSSCs). Type 1 dyes incorporating the donor segment directly to the diketopyrrolopyrrole core lead to a better electron communication between the donor and acceptor, allowing an efficient charge transfer process. Type 2 and Type 3 dyes with a phenyl unit between the donor and diketopyrrolopyrrole unit show lower delocalization of the excited state. Compared with Type 3 dyes, Type 1 dyes exhibit higher conjugated skeleton co planarity and shorter electron …
Pillar[5]arene-Diketopyrrolopyrrole Fluorescent Copolymer: A Promising Recognition and Adsorption Material for Adiponitrile by Selective Formation of…
2017
Conjugated pillar[5]arene-diketopyrrolopyrrole copolymer (P1) is synthesized by the copolymerization of a difunctionalized pillar[5]arene and a diketopyrrolopyrrole-based monomer, which shows large extinction coefficients (1.1 × 104 m-1 cm-1 ) at 519 nm and strong emission at 587 nm. P1 exhibits very strong host-guest binding affinity towards adiponitrile but low binding affinity towards 1,4-dihalobutane and 1,4-bis(imidazol-1-yl)butane. Such an enhanced selectivity is first found in the polypseudorotaxane between pillararene and neutral guests in organic solution and is successfully used for the recognition and adsorption of adiponitrile by the formation of a P1-adiponitrile polypseudorota…
Heavy-ion induced single event effects and latent damages in SiC power MOSFETs
2022
The advantages of silicon carbide (SiC) power MOSFETs make this technology attractive for space, avionics and high-energy accelerator applications. However, the current commercial technologies are still susceptible to Single Event Effects (SEEs) and latent damages induced by the radiation environment. Two types of latent damage were experimentally observed in commercial SiC power MOSFETs exposed to heavy-ions. One is observed at bias voltages just below the degradation onset and it involves the gate oxide. The other damage type is observed at bias voltages below the Single Event Burnout (SEB) limit, and it is attributed to alterations of the SiC crystal-lattice. Focused ion beam (FIB) and s…
High electrical conductance of single molecules: a challenge in the series of conjugated oligomers.
2009
En route to molecular electronics: As extended, conjugated oligomers are desirable for molecular electronics, their electrical conductance should display a low attenuation factor. Zinc-complexed oligo(ethynyleneporphyrindiylethynylene)s have been prepared that are distinguished by ultralow attenuation factors in single-molecule conductance.