Search results for "Microscopy"
showing 10 items of 3390 documents
Near-field probing of active photonic-crystal structures
2002
We report a study of the optical near field of an active integrated component operating near the 1.55-mum telecommunications wavelength. The device is based on a two-dimensional photonic crystal etched in a suspended InP membrane. Topographic as well as optical information is collected by use of a scanning near-field optical microscope in collection mode, providing information about the local distribution of the losses.
Ambipolar MoS2 Transistors by Nanoscale Tailoring of Schottky Barrier Using Oxygen Plasma Functionalization
2017
One of the main challenges to exploit molybdenum disulfide (MoS2) potentialities for the next-generation complementary metal oxide semiconductor (CMOS) technology is the realization of p-type or ambipolar field-effect transistors (FETs). Hole transport in MoS2 FETs is typically hampered by the high Schottky barrier height (SBH) for holes at source/drain contacts, due to the Fermi level pinning close to the conduction band. In this work, we show that the SBH of multilayer MoS2 surface can be tailored at nanoscale using soft O-2 plasma treatments. The morphological, chemical, and electrical modifications of MoS2 surface under different plasma conditions were investigated by several microscopi…
Impact of Gamma Radiation on Dynamic RDSON Characteristics in AlGaN/GaN Power HEMTs
2019
GaN high-electron-mobility transistors (HEMTs) are promising next-generation devices in the power electronics field which can coexist with silicon semiconductors, mainly in some radiation-intensive environments, such as power space converters, where high frequencies and voltages are also needed. Its wide band gap (WBG), large breakdown electric field, and thermal stability improve actual silicon performances. However, at the moment, GaN HEMT technology suffers from some reliability issues, one of the more relevant of which is the dynamic on-state resistance (R) regarding power switching converter applications. In this study, we focused on the drain-to-source on-resistance (R) characteristic…
3D Bioprinting for Vascularized Tissue-Engineered Bone Fabrication
2020
Vascularization in bone tissues is essential for the distribution of nutrients and oxygen, as well as the removal of waste products. Fabrication of tissue-engineered bone constructs with functional vascular networks has great potential for biomimicking nature bone tissue in vitro and enhancing bone regeneration in vivo. Over the past decades, many approaches have been applied to fabricate biomimetic vascularized tissue-engineered bone constructs. However, traditional tissue-engineered methods based on seeding cells into scaffolds are unable to control the spatial architecture and the encapsulated cell distribution precisely, which posed a significant challenge in constructing complex vascul…
Scanning electrochemical microscopy and electrochemical impedance spectroscopy-based characterization of perforated polycarbonate membrane modified b…
2021
Abstract In this research, scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS) were applied for the evaluation of surface characteristics of electrochemical (amperometric) biosensor based on two composite structures consisting of perforated polycarbonate membrane modified by carbon-nanomaterials and glucose oxidase. The first structure consisted of the polycarbonate filter membrane, punctured by 400 nm holes (PCM) consequently modified with single walled carbon nanotubes (SWCNT) and graphene oxide (GO) layer (PCM/SWCNT/GO); and the other structure consisted of the same PCM, consequently modified with SWCNT and reduced graphene oxide (rGO) layer (PCM/S…
<br /> Ga_2O_3 films alloyed with SnO_2 and treated by RF plasma: an interesting way for the development of transparent contacts for UV-emittin…
2016
International audience; Layers of Ga2O3 alloyed up to 15 at% with Sn4+ has been studied after treatment by RF plasma. An increased conductivity was measured which is an interesting step towards transparent contacts for UV-emitting photonics devices.
Tuning four-wave mixing through temperature in ethanol-filled photonic crystal fiber
2016
In this paper, continuous tuning of four-wave mixing bands in an ethanol-filled photonic crystal fiber is investigated. A wide tuning range of the parametric bands, from 745 nm to 920 nm (signal) and from 1260 nm to 1710 nm (idler), is achieved through the thermo-optic effect. This corresponds to a frequency tuning range higher than 2000 cm−1; such wide range can be particularly useful in applications that require broadband wavelength conversion, e.g., CARS microscopy. Numerical calculations are in good agreement with experimental measurements.
Tailoring of highly porous SnO2 and SnO2-Pd thin films
2019
Abstract Tin oxide is a material that attracts attention due to variety of technological applications. The main parameters that influence its properties are morphology, crystalline structure and stoichiometry. Researchers try to develop nanostructured thin films with tunable parameters that would conform its technological applications. Herein, we report on the preparation and characterization of highly porous SnO2 and Pd-doped SnO2 thin films. These films were deposited in the form of nanorods with controllable geometry. Such morphology was achieved by utilizing glancing angle deposition (GLAD) with assisted magnetron sputtering. This arrangement allowed preparation of slanted pillars, zig-…
Single molecule imaging using a highly confined optical field at a triangular aperture
2005
We demonstrate that scanning near-field optical microscopy based on a probe with a triangular aperture is capable of imaging single fluorescent molecules with an optical resolution of 30 nm. Numerical simulations agree well with experiment.
Environmental chamber for an atomic force microscope.
2007
A commercial atomic force microscope (AFM), originally designed for operation in ambient conditions, was placed inside a compact aluminum chamber, which can be pumped down to high vacuum levels or filled with a desired gaseous atmosphere, including humidity, up to normal pressure. The design of this environmental AFM is such that minimal intrusion is made to the original setup, which can be restored easily. The performance inside the environmental chamber is similar to the original version.