Chemical sensor based on a novel capacitive microwave flexible transducer with polymer nanocomposite-carbon nanotube sensitive film

Microsystem Technologies - This study presents the results on the feasibility of a resonant planar chemical capacitive sensor in the microwave frequency range suitable for gas detection and...     

Nonlinear effects in T-branch junctions

The negative potential appearing at the central branch of T-branch junctions (TBJs) when biasing left and right contacts in push-pull fashion has been found to appear under high biasing not only for short (ballistic) TBJs but also for long (diffusive) ones. By means of a microscopic Monte Carlo simulation we are able to explain this nonlinear effect as a consequence of intervalley scattering mechanisms leading to the emergence of an accumulation domain that modifies the electronic potential profile within the devices.     

Further studies on the lithium phosphorus oxynitride solid electrolyte

First step in the way to the fabrication of an all-solid microbattery for autonomous wireless sensor node, amorphous thin solid films of lithium phosphorus oxynitride (LiPON) were prepared by radio-frequency sputtering of a mixture target of P₂O₅/Li₂O in ambient nitrogen atmosphere. The morphology, composition, and ionic conductivity were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and A.C. impedance spectroscopy. With a thickness of 1.4 μm, the obtained LiPON amorphous layer provided an ionic conductivity close to 6 × 10⁻⁷ S cm⁻¹ at room temperature. MicroRaman UV spectroscopy study was successfully carried out for the first time on LiPON thin films to complete the characterization and bring further information on LiPON structure.     

Recent developments in MEMS-based miniature fuel cells

Micro fuel cells (μ-FCs) represent promising power sources for portable applications. Today, one of the technological ways to make μ-FCs is to have recourse to standard microfabrication techniques used in the fabrication of micro-electro-mechanical systems (MEMS). This paper shows an overview on the applications of MEMS techniques on miniature FCs by presenting several solutions developed throughout the world. It also describes the latest developments of a new porous silicon-based miniature fuel cell. Using a silane grafted on an inorganic porous media as the proton-exchange membrane instead of a common ionomer such as Nafion^®, the fuel cell achieved a maximum power density of 58 mW cm^?2 at room temperature with hydrogen as fuel.     

A Porous Silicon‐Based Ionomer‐Free Membrane Electrode Assembly for Miniature Fuel Cells

Previous work showed the pertinence of using grafted porous silicon as the proton exchange membrane for miniature fuel cells. One of the limitations was the membrane‐electrodes assembly, which required an ionomer, in the current study a 5% Nafion®‐117 solution, to ensure a proton‐conducting link between the commercial carbon cloth electrodes and the membrane. Here, new developments for this fuel cell, with a totally Nafion®‐free process, are reported. The Pt catalyst is sputtered and electrodeposited onto the surface of the proton conducting porous silicon membrane. The initial performance of this fuel cell is shown and demonstrates the validity of the technique.