F. Brunetti

Carbon Nanotubes Films for Sensing Applications: From Piezoresistive Sensor to Gas Sensing

In this work we present the study of the sensing properties of Carbon nanotube films. We show the realization of deformation sensors based on composite CNT-polymer films realized by electrochemical deposition starting from a dispersion of SWCNTs and EDOT monomer. The gauge factor (GF) of the sensors has been found to be up to 3–4 times higher than that of the commercial strain gauge. We show also that the CNT have gas sensing properties, that can be applied to different gases, included H2O in gaseous form. Detection can be optimized by means of electrostatic polarization of the film substrate.

Controlled growth of ordered SWCNTs for the realization of multielectrode field emitter devices

The growth of single wall carbon nanotubes (SWCNTs) on selected patterned substrates is the fundamental step for the realization of many devices based on SWCNTs. In this work, we show that the growth technique based on chemical vapor deposition (CVD) is perfectly suitable for the realization of prototypal devices such as efficient field emitters. Many different characterization techniques are used to check the SWCNT growth. Scanning electron microscopy (SEM) and Raman spectroscopy are extensively used to monitor the structural properties of our samples. We characterize the field emission in our systems, and investigate the realization of lithographically patterned multilayer structures for the realization of a multielectrode device able to control the intensity of field emission.

Carbon nanotube/conducting polymer composites for electronic application: materials preparation and devices assembling

In this work, we describe the preparation of patterned carbon nanotubes/conducting polymers composite electrode. The synthetic methodology consists in an in situ electropolymerization of the monomer in the presence of nanotubes on a prepatterned anode. Two kinds of polymers were investigated: PEDOT and poly (1-8 DAN), and some nanotubes pretreatments were studied. The effect of these procedures was evaluated and discussed.

Towards a THz backward wave amplifier in European OPTHER project

Within the EC funded international project OPTHER (OPtically Driven TeraHertz AmplifiERs) a considerable technological effort is being undertaken, in terms of technological development, THz device design and integration. The ultimate goal is to develop a miniaturised THz amplifier based on vacuum-tube principles The main target specifications of the OPTHER amplifier are the following: - Operating frequency: in the band 0.3 to 2 THz - Output power: > 10 mW ( 10 dBm ) - Gain: 10 to 20 dB. The project is in the middle of its duration. Design and simulations have shown that these targets can be met with a proper device configuration and careful optimization of the different parts of the amplifier. Two parallel schemes will be employed for amplifier realisation: THz Drive Signal Amplifier and Optically Modulated Beam THz Amplifier.

FP7-CHEETAH Knowledge Exchange Platform: Results and their Exploitation

FP7-CHEETAH is a combinat ion of a collaborat ive project (CP) and a coordinat ion and support act ion (CSA), receiving funding from the European Union under grant agreement No 609788. The project aims at solving specific R&D issues to overcome fragment at ion of European PV R&D and to accelerate the indust rializat ion of innovat ions by intensifying the collaborat ion between R&D providers and indust ry. This proceeding reports on the st rategy and key tools brought by the CHEETAH project to improve the state of the art in knowledge exchange on PV RTD. It s CHEETAH Knowledge Exchange Plat form (KEP) features a dynamic database, a powerful build-in search engine, the dedicated e-learning plat form for on-line meet ings with internal and external stakeholders, webinars, on-line tests and experiments. The portal profits from the best pract ice in more efficient social and professional networks web portal by represent ing a significant step forward in knowledge exchange for the European photovoltaics community to support t raining, share knowledge and research infrast ructures and foster collaborat ion opportunit ies at EU scale

Low capacitance vacuum microtriode for high frequency operation

In this work a new triode geometry has been designed to reduce the cathode-gate capacitance with respect to the classic Spindt Type microtriodes. With this configuration, the cut off frequency has been increased up to 156 GHz, about 3 times bigger when compared to the standard configuration.

Field emission microgun for THz amplifiers

In this work we describe the design of a field emission microgun and the optimization of geometrical and electrical characteristics in order to achieve an electron source to be used in a vacuum THz amplifier. The microgun has a circle beam with a current of about 3mA and energy of 8 keV with a perveance of 0,0042 µP.

Field emission vacuum triode: THz waveguide solutions for the transmission lines

A complete microwave characterization of the small-signal properties in terms of S-parameters behaviors of a flip-chip triode geometry device has been studied with CST simulator. The simulation results of a single triode and 10times10 triode array have been proposed.

Innovative design of nano-vacuum triode

An innovative procedure for the realization and the assembly of vacuum triode based on carbon nanotube cold cathode is proposed. The aim of the proposed technique is to avoid the typical problem due to the growth of carbon nanotube in the triode structure. The obtained electrical properties of the realized triode fully confirm the validity of the technique.

Towards the realization of a multielectrode field emission device: controlled growth of single wall carbon nanotube arrays

We reported the design and realization of a carbon nanotube-based integrated multielectrode device. Patterned Si/SiO2/Nb/Nb2O5 multilayer was successfully realized by means of a few, common photolithographic processes with the minimum number of mask alignment steps. Such structure constitutes the patterned substrate of successive Hot Filament Chemical Vapour Deposition (HFCVD) process. Selective growth of highly oriented SWCNT arrays was obtained in the predefined locations while survival of the entire structure was achieved. Field emission measurements of such materials were carried out. Good and reproducible field emission behaviour has been observed in several realized structures.