In this work, we demonstrate a fully integrated three-axis Hall magnetic sensor by exploitingmicrofabrication technologies applied to a GaAs-based heterostructure. This allows us toobtain, by the same process, three mutually orthogonal sensors: an in-plane Hall sensor andtwo out-of-plane Hall sensors. The micromachined devices consist of a two-dimensionalelectron gas AlGaAs/InGaAs/GaAs multilayer which represents the sensing structure, grownon the top of an InGaAs/GaAs strained bilayer. After the release from the substrate, thestrained bilayer acts as a hinge for the multilayered structure allowing the out-of-planeself-positioning of devices. Both the in-plane and out-of-plane Hall sensors show a linearresponse versus the magnetic field with a sensitivity for current-biased devices higher than1000 V A-1 T-1, corresponding to an absolute sensitivity more than 0.05 V T-1 at 50 ?A.Moreover, Hall voltage measurements, as a function of the mechanical angle for both in-planeand out-of-plane sensors, demonstrate the potential of such a device for measurements of thethree vector components of a magnetic field.

This paper presents a new AlN-based MEMS devices suitable for vibrational energy harvesting applications. Due to their particular shape and unlike traditional cantilever which efficiently harvest energy only if subjected to stimulus in the proper direction, the proposed devices have 3D generation capabilities solving the problem of device orientation and placement in real applications. Thanks to their particular shape, the realized devices present more than one fundamental resonance frequencies in a range comprised between 500 Hz and 1.5 kHz, with a voltage generation higher than 300?V and an output power up to 0.4 pW for single MEMS device.

This paper presents a self-rolled metalized InGaAs/GaAs bi-layer suitable to be used for magnetic field mapping applications. Numerical and preliminary experimental results will be presented demonstrating that the proposed micro-tube structure is an optimum candidate to be used as THz collector of electromagnetic energy.

Herein we describe the realization of nanowalled polymeric microtubes through a novel andversatile approach combining the layer-by-layer (LbL) deposition technique, the self-rolling ofhybrid polymer/semiconductor microtubes and the subsequent removal of the semiconductortemplate. The realized channels were characterized in detail using scanning electron and atomicforce microscopes. Additionally, we report on the incorporation of a dye molecule within thenanowalls of such microtubes, demonstrating a distribution of the fluorescence signalthroughout the whole channel volume. This approach offers the possibility to tailor theproperties of micro/nanotubes in terms of size, wall thickness and composition, thus enablingtheir employment for several applications.

In this paper it is reported a novel approach for the fabrication of polymeric microtubes based on the combination of semiconductor strain released thin films and Layer-by-Layer (LbL) deposition technique. The structure consisting of a LbL self-assembled polylectrolytes (PEs) film deposited onto a strained GaAs/InGaAs bilayer, was properly patterned and structured to enable the self rolling of an array of channels of different lengths. Then, the semiconductor film, acting as a sacrificial template, was selectively etched to obtain polymer microtubes. The so-realized polymeric channels were characterized in detail using Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM). Additionally, such microtubes were analyzed by confocal microscopy to prove the successful incorporation of a dye molecule within the polymeric nanowalls.

In this work, we report on the fabrication and characterization of stress-driven aluminum nitride (AlN) cantilevers to be applied as flow sensor for fish lateral line system. The fabricated structures exploit a multilayered cantilever AlN/molybdenum (Mo) and a Nichrome 80/20 alloy as piezoresistor. Cantilever arrays are realized by using conventional micromachining techniques involving optical lithography and etching processes. The fabrication of the piezoresistive cantilevers is reported and the operation of the cantilever as flow sensor has been investigated by electrical measurement under nitrogen flowing condition showing a sensitivity to directionality and to low value applied forces.

The integration of a polycrystalline material such as aluminum nitride (AlN) on a flexible substrate allows the realization of elastic tactile sensors showing both piezoelectricity and significant capacitive variation under normal stress. The application of a normal stress on AlN generates deformation of the flexible substrate on which AlN is grown, which results in strain gradient of the polycrystalline layer. The strain gradient is responsible for an additional polarization described in the literature as the flexoelectric effect, leading to an enhancement of the transduction properties of the material. The flexible AlN is synthesized by sputtering deposition on kapton HN (poly 4,4?- oxydiphenyl pyromellitimide) in a highly oriented crystal structure. High orientation is demonstrated by X-ray diffraction spectra (FWHM = 0.55° of AlN (0002)) and HRTEM. The piezoelectric coefficient d 33 and stress sensitive capacitance are 4.7 ± 0.5 pm V -1 and 4 × 10 -3 pF kPa -1, respectively. The parallel plate capacitors realized for tactile sensing present a typical dome shape, very elastic under applied stress and sensitive in the pressure range of interest for robotic applications (10 kPa to 1 MPa). The flexibility of the device finalized for tactile applications is assessed by measuring the sensor capacitance before and after shaping the sensing foil on curved surfaces for 1 hour. Bending does not affect sensor's operation, which exhibits an electrical Q factor as high as 210, regardless of the bending, and a maximum capacitance shift of 0.02%.

A model for realistic InAs quantum dot composition profile is proposed and analyzed, consisting of a double region scheme with an In-rich internal core and an In-poor external shell, in order to mimic the atomic scale phenomena such as In-Ga intermixing and In segregation during the growth and overgrowth with GaAs. The parameters of the proposed model are derived by reproducing the experimentally measured polarization data. Further understanding is developed by analyzing the strain fields which suggests that the two-composition model indeed results in lower strain energies than the commonly applied uniform composition model.

Electroactive microelectromechanical device of the Artificial Hair Cell type, comprising a moving cilium structure including a substrate (11, 12; 42) and a cantilever (18; 48), partly or entirely in.piezoelectric material, subject to bending or deformation following the action of a force and/or an applied voltage (Vapp1), said cantilever (18; 48) comprising a multilayer (13, 14a, 14b, 16) inducing a stress-driven geometry in which a portion (19) of said cantilever (18; 48) lies outside of a plane defined by the substrate (11, 12; 42). According to the invention said cantilever (18; 48) is associated to a piezoresistive element, in particular of piezoresistive material (15) configured to measure the bending or deformation of said cantilever (18; 48).

The present invention concerns an integrated triaxial magnetic sensor device 100 apt to detect a magnetic field comprising: a substrate 120 having a surface defining a reference plane (x,y); a first sensor unit 101 arranged on a first main surface 121 of the substrate in a first plane substantially parallel to the reference plane; a second sensor unit 102 arranged on a second plane, and a third sensor unit 103 arranged on a third plane, the second and third planes being not parallel to the reference plane. The device further comprises: a first cantilever structure 115 raised with respect to the reference plane by a first elevation angle and having a second main surface 125 arranged along the second plane, the first cantilever structure including the second sensor unit 102, and a second cantilever structure 116 raised with respect to the reference plane by a second elevation angle and having a third main surface 126 arranged along the third plane, the second cantilever structure including the third sensor unit 103, in which the first and the second cantilever structure are structurally connected to the substrate 120 through a respective first and second hinge structure 113, 114 curved with respect to the reference plane and bearing the respective cantilever structure while maintaining it raised with respect to the reference plane.