Remote dynamic actuation of an electrostatically driven microcantilever by a wireless power transfer system

Altres ajuts: acord transformatiu CRUE-CSICThe design, modelling, fabrication and test of a device prototype, based on a microcantilever capacitively connected to a folded-end half-wave dipole antenna, which is remotely actuated by a wireless power transfer (WPT) system are presented here. The microcantilever and the antenna, which are coupled at the antenna feeding point, work as a new device, is able to harness the radiated energy wirelessly transferred from an emitter antenna to directly excite the mechanical vibration modes of the microcantilever. The response to an amplitude-modulated (AM) RF radiated signal excitation produced by a transmitting antenna is experimentally analysed and fit to a simple model when the distance between both antennas varies from the near field to the radiated far field regime

Piezoelectric monolayers as nonlinear energy harvesters

We study the dynamics of h-BN monolayers by first performing ab-initio calculations of the deformation potential energy and then solving numerically a Langevine-type equation to explore their use in nonlinear vibration energy harvesting devices. An applied compressive strain is used to drive the system into a nonlinear bistable regime, where quasi-harmonic vibrations are combined with low-frequency swings between the minima of a double-well potential. Due to its intrinsic piezoelectric response, the nonlinear mechanical harvester naturally provides an electrical power that is readily available or can be stored by simply contacting the monolayer at its ends. Engineering the induced nonlinearity, a 20 nm device is predicted to harvest an electrical power of up to 0.18 pW for a noisy vibration of 5 pN

Combined laser and atomic force microscope lithography on aluminum: Mask fabrication for nanoelectromechanical systems

A direct-write laser system and an atomic force microscope(AFM) are combined to modify thin layers of aluminum on an oxidizedsilicon substrate, in order to fabricate conducting and robust etch masks with submicron features. These masks are very well suited for the production of nanoelectromechanical systems(NEMS) by reactive ion etching. In particular, the laser-modified areas can be subsequently locally oxidized by AFM and the oxidized regions can be selectively removed by chemical etching. This provides a straightforward means to define the overall conducting structure of a device by laser writing, and to perform submicron modifications by AFMoxidation. The mask fabrication for a nanoscale suspended resonator bridge is used to illustrate the advantages of this combined technique for NEMS

Inducing bistability with local electret technology in a microcantilever based non-linear vibration energy harvester

A micro-electro-mechanical system based vibration energy harvester is studied exploring the benefits of bistable non linear dynamics in terms of energy conversion. An electrostatic based approach to achieve bistability, which consists in the repulsive interaction between two electrets locally charged in both tip free ends of an atomic force microscope cantilever and a counter electrode, is experimentally demonstrated. A simple model allows the prediction of the measured dynamics of the system, which shows an optimal distance between the cantilever and the counter electrode in terms of the root mean square vibration response to a colored Gaussian excitation noise

Predictive model for scanned probe oxidation kinetics

Previous descriptions of scanned probe oxidation kinetics involved implicit assumptions that one-dimensional, steady-state models apply for arbitrary values of applied voltage and pulse duration. These assumptions have led to inconsistent interpretations regarding the fundamental processes that contribute to control of oxide growth rate. We propose a model that includes a temporal crossover of the system from transient to steady-state growth and a spatial crossover from predominantly vertical to coupled lateral growth. The model provides an excellent fit of available experimental data

Localized and distributed mass detectors with high sensitivity based on thin-film bulk acoustic resonators

A mass sensor based on thin-film bulk acoustic resonator, intended for biomolecular applications, is presented. The thin film is a (002) AlN membrane, sputtered over Ti/Pt on a (001) Si wafer, and released by surface micromachining of silicon. Two experiments are proposed to test the mass sensing performance of the resonators: (a) distributed loading with a MgF2 film by means of physical vapor deposition and (b) localized mass growing of a C/Pt/Ga composite using focused-ion-beam-assisted deposition, both on the top electrode. For the distributed and localized cases, the minimum detectable mass changes are 1.58×10−8g/cm2 and 7×10−15g, respectively

Ultrasensitive mass sensor fully integrated with complementary metal-oxide-semiconductor circuitry

Nanomechanical resonators have been monolithically integrated on preprocessed complementary metal-oxide-semiconductor(CMOS) chips. Fabricatedresonatorsystems have been designed to have resonance frequencies up to 1.5 MHz. The systems have been characterized in ambient air and vacuum conditions and display ultrasensitive mass detection in air. A mass sensitivity of 4ag/Hz has been determined in air by placing a single glycerine drop, having a measured weight of 57 fg, at the apex of a cantilever and subsequently measuring a frequency shift of 14.8 kHz. CMOS integration enables electrostatic excitation, capacitive detection, and amplification of the resonance signal directly on the chip

A flexible dipole antenna for direct transduction of microwave radiated power into DC mechanical deflection

Acord transformatiu CRUE-CSICA new device resulting from the merging of mechanical and electromagnetic properties of a couple of conductive cantilevered beams is described in this paper. The device, which is based on two metallic clamped-free beams which, at the same time, are the arms of a radio frequency dipole antenna is capable to receive the electromagnetic power radiated from an emitting antenna and transduce it directly in a dc mechanical actuation. A numerical model developed to describe the behavior of the device has been validated through the test of a millimeter scale demonstrator working in the microwave frequency band

ICT - Energy - Concepts Towards Zero - Power Information and Communication Technology

A sustainable future for our information society relies on bridging the gap between the energy required to operate portable ICT devices with the energy available from portable/mobile sources. The only viable solution is attacking the gap from both sides, i.e. to reduce the amount of energy dissipated during computation and to improve the efficiency in energy harvesting technologies. This requires deeper and broader knowledge of fundamental processes and thorough understanding of how they apply to materials and engineering at the nanoscale, all the way up to the design of energy-efficient electronics. This textbook is a first attempt to discuss such concepts towards Zero-Power ICT. The content is accessible to advanced undergraduates and early year researchers fascinated by this topic. The book is realized through the EU-funded ZEROPOWER project. </span