Film Bulk Acoustic Resonator Based on Zinc Oxide Thin Film

A piezoelectric thin film sandwiched between two metal electrodes is basic structure for high frequency bulk acoustic wave devices. For that propose, the RF magnetron sputtering deposition for piezoelectric ZnO film formation and its such application for film bulk acoustic resonator (FBAR) devices are presented. Several critical parameters of the RF magnetron sputtering process deposition pressure, RF power, substrate temperature, O2 concentration and the target to substrate distance were determined to clarify their effects on the material characteristics of the ZnO. Highly c-axis oriented thin films as thick as 5.7 mm were grown and analyzed. Compressive stresses were observed. The FBAR devices with the ZnO films exhibited a pronounced resonance peak centred at 537 MHz with a k2 coupling coefficient of 7 %. It found therefore that the impedance matching of the FBAR could be easily achieved simply by controlling the resonance the resonator. Keywords: ZnO; FBAR; R.F sputtering magnetron; resonator

Harvesting indoor light to supply power to nomad embedded systems

International audienceIt is possible to design a system to supply power to low consumption systems (hundreds of µW to tens of mW) from industrial devices. To develop an autonomous system based on harvesting energy from mixed artificial and natural light, it is mandatory to know which solutions are available and suitable to the conditions of use of the system to be designed. In this paper a comparison of solar cells exposed to different indoor light sources is made. This allows to establish which technology is the most relevant to use in different light environments, in terms of power generation. In addition, the difference in behavior between the two most widely produced solar cells, crystallin and amorphous Si, is depicted. We conclude that for new efficient light sources as fluorescent tubes, CFLs and LEDs, amorphous silicon is the best solution to generate power. On the other hand, crystallin silicon is the most efficient under incandescent, halogen or sunlight exposition

RETRATO SIN IDENTIFICAR [Material gráfico]

Copia digital. Madrid : Ministerio de Educación, Cultura y Deporte, 201

The Effect of the Oxygen Concentration on the Zinc Oxide Films Properties Deposited by Magnetron Sputtering

The influences of the oxygen concentration variation on the zinc oxide films structural properties were studied. ZnO films were deposited on silicon substrate by rf magnetron sputtering in reactive plasma using a zinc oxide target. They exhibited a c-axis orientation of below 0.32° FWHM of X-ray rocking curves, an extremely high resistivity of 1012 ?cm and an energy gap of 3.3 eV at room temperature. It was found that a substrate temperature of 100°C, very low gas pressures of 3.35x10-3 Torr in argon and oxygen mixed gas atmosphere giving to ZnO thin films a good homogeneity and a high crystallinity. Measurements of the ac conductivity properties of ZnO sandwich structures with silver and platinum electrodes are reported. The frequency dependence of the both the ac conductivity and dielectric constant of thin films of ZnO have been investigated in the frequency range 5Khz-13Mhz. It is shown that the total ac conductivity ; obeys the equations  where s is an index which increases with frequency and decreases with temperature. The dielectric constant, , lies in the range 8–9 at room temperature and is independent of the frequency in the dielectric thin films.   Keywords: ZnO; R.F sputtering magnetron; X-ray diffraction; conductivity; electrical properties; dielectric properties; optical properties

Energies Renouvelables Numériques

International audienc

Méthodes Numériques pour les Energies Renouvelables

International audienc

L’incidence du numérique sur les collaborations interdisciplinaires en recherche : les enjeux techniques et les problématiques juridiques du lieu de vie connecté

International audienc

Présentation du projet RIDER : Réseau et Interconnectivité Des Énergies Renouvelables

Introduction L’un des piliers fondamentaux de nos sociétés humaines est certainement la communication. Depuis le « Nenikamen » du coureur de Marathon (490 avant J.-C.) jusqu’à nos jours il est aisé de mesurer non seulement les évolutions technologiques des moyens de communication mais aussi et surtout l’impact que ces dernières ont induit, produit, sur nos sociétés. En effet, au tout début de nos sociétés humaines était le sage, l’homme posé, qui tel une « éponge », engloutissait les informat..

Etude et réalisation de capteurs d'humidité (Capteur à détection optique, capteur piézoélectrique à base de couche d'oxyde de zinc)

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Microstructures thermoélectriques élaborés par évaporation flash : applications aux microcapteurs thermiques

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF