Search results for "fabrication"

Strongly-coupled PbS QD solids by doctor blading for IR photodetection

2016

Solution-processed QD solids are emerging as a novel concept for high-performance optoelectronic devices. In this work, doctor blading is proposed for the fabrication of strongly-coupled QD solids from a PbS nanoink for photodetection at telecom wavelengths. The key step of this procedure is the solid-state ligand exchange, which reduces the interparticle distance and increases the carrier mobility in the resulting strongly-coupled QD solid. This is accomplished by replacing the original long oleylamine molecules by shorter molecules like 3-mercaptopropionic acid, as confirmed by FTIR, TGA and XPS. Further, a detailed investigation with XPS confirms the air-stability of the QD solids and th…

Carbon nanotubes as electrodes for dielectrophoresis of DNA

2006

Dielectrophoresis can potentially be used as an efficient trapping tool in the fabrication of molecular devices. For nanoscale objects, however, the Brownian motion poses a challenge. We show that the use of carbon nanotube electrodes makes it possible to apply relatively low trapping voltages and still achieve high enough field gradients for trapping nanoscale objects, e.g., single molecules. We compare the efficiency and other characteristics of dielectrophoresis between carbon nanotube electrodes and lithographically fabricated metallic electrodes, in the case of trapping nanoscale DNA molecules. The results are analyzed using finite element method simulations and reveal information abou…

Dielectrophoretic trapping of multilayer DNA origami nanostructures and DNA origami-induced local destruction of silicon dioxide

2015

DNA origami is a widely used method for fabrication of custom-shaped nanostructures. However, to utilize such structures, one needs to controllably position them on nanoscale. Here we demonstrate how different types of 3D scaffolded multilayer origamis can be accurately anchored to lithographically fabricated nanoelectrodes on a silicon dioxide substrate by DEP. Straight brick-like origami structures, constructed both in square (SQL) and honeycomb lattices, as well as curved "C"-shaped and angular "L"-shaped origamis were trapped with nanoscale precision and single-structure accuracy. We show that the positioning and immobilization of all these structures can be realized with or without thi…

Fabrication of cobalt and cobalt oxide/graphene composites: towards high-performance anode materials for lithium ion batteries.

2010

Design, fabrication, and analysis of a spin-valve based current sensor

2004

Abstract In this work, we suggest a novel current sensor design, based on spin valve technology, with a full Wheatstone bridge configuration. The principal characteristic is that the four magnetoresistance sensing elements, fully active, are deposited and patterned at the same time. This way, differences among them should be insignificant, so improving voltage offset and drift temperature parameters. The complete IC fabrication process involves only three lithography steps, making the process cheaper and faster. In order to get a balanced bridge, the measured current must be properly driven, by means of an auxiliary PCB. Some prototypes, with different input impedances, have been fabricated…

Development of micro chemical, biological and thermal systems in China: A review

2010

The interest in micro technologies for application in chemical, biological and thermal systems has increased considerably in China because microreactors or microfluidics in general demonstrate some remarkably advantages such as inherent miniaturization and portability, intensification of heat and mass transfer, quick analysis results, high-throughput and low consumption of reagents. This review focuses on the recent advances in the micro technologies in China including microreactor-based systems for chemical processing and analysis, biological microfluidics for DNA analysis, cell handling and analysis, separation based detection, protein based applications and immunoassays, micro heat trans…

Opals infiltrated with a stimuli-responsive hydrogel for ethanol vapor sensing

2013

We report on a novel class of optical materials for ethanol vapor sensing, based on polystyrene opals infiltrated with an innovative stimuli responsive hydrogel. We describe the fabrication process of the bare polystyrene opals and their subsequent infiltration. The optical characterization of the photonic crystal templates was performed to prove the good quality of the samples. Measurements on the infiltrated opals showed that the transmission spectra in the visible range strongly change at varying concentrations of ethanol vapor. The fabricated structures show a linear optical response in the visible range, for high values of ethanol concentration.

Biofabrication of 3D tumor models in cancer research

2020

Abstract Tumors are complex tissues in which cancer cells are interwoven with fibroblasts, endothelial cells, pericytes, and inflammatory cells; these cells and the extracellular matrix constitute the tumor microenvironment (TME). The TME can modulate the behavior of tumor cells in terms of capacity to invade neighboring or distant tissues and drug resistance, by secreting tumor-promoting growth factors and cytokines. The poor efficacy of many anticancer drugs in clinical trials can be partly justified by the lack of predictive preclinical models. Prior to in vivo testing, biofabrication of tools for investigation in three-dimensional (3D) could be useful. Indeed, cells grown in 3D matrices…

Estimation des performances, test et contrôle des systèmes cyber-physiques employant des réseaux de communication non idéaux

2020

Wireless technology is a key enabler of the promises of Industry 4.0 (Smart Manufacturing). As such, wireless technology will be adopted as a principal mode of communication within the factory beginning with the factory enterprise and eventually being adopted for use within the factory workcell. Factory workcell communication has particular requirements on latency, reliability, scale, and security that must first be met by the wireless communication technology used. Wireless is considered a non-ideal form of communication in that when compared to its wired counterparts, it is considered less reliable (lossy) and less secure. These possible impairments lead to delay and loss of data in indus…

Optimized substrates and measurement approaches for Raman spectroscopy of graphene nanoribbons

2019

The on-surface synthesis of graphene nanoribbons (GNRs) allows for the fabrication of atomically precise narrow GNRs. Despite their exceptional properties which can be tuned by ribbon width and edge structure, significant challenges remain for GNR processing and characterization. In this contribution, we use Raman spectroscopy to characterize different types of GNRs on their growth substrate and to track their quality upon substrate transfer. We present a Raman-optimized (RO) device substrate and an optimized mapping approach that allows for acquisition of high-resolution Raman spectra, achieving enhancement factors as high as 120 with respect to signals measured on standard SiO2/Si substra…