Disclosed are methods and apparatus for depositing uniform layers on a substrate (201) for piezoelectric applications. An ultra-thin seed layer (308) having a uniform thickness from center to edge thereof is deposited on a substrate (201). A template layer (310) closely matching the crystal structure of a subsequently formed piezoelectric material layer (312) is deposited on a substrate (201). The uniform thickness and orientation of the seed layer (308) and the template layer (310), in turn, facilitate the growth of piezoelectric materials with improved crystallinity and piezoelectric properties.

A method of preparing a piezoelectric single crystal with high piezoelectricity and near- perfect transparency. The method includes depositing electrodes on two opposition surfaces of a piezoelectric single crystal which is a ferroelectric crystal; AC-poling the piezoelectric single crystal through the electrodes by repeatedly changing polarity of an AC electric field; and after polarization, removing the electrodes on the two opposition surfaces of the piezoelectric single crystal and then depositing Ag nanowire or indium tin oxide (ITO) as electrodes on the two opposition surfaces of the piezoelectric single crystal. Repeatedly changing the polarity of the polarized electric field can increase the domain size of the ferroelectric crystal, or reduce the domain wall density of the domain structure, thereby improving the transparency of the piezoelectric single crystal having high piezoelectric.

A functionalized object includes at least one mechanical wave sensor providing the object with a vibration and deformation detection capability. The mechanical wave sensor comprises: a sensitive cell having a thickness less than or equal to 50 microns, and comprising an active layer made of a monocrystalline or polycrystalline piezoelectric material and two electrodes, which are in contact with the active layer and accessible at a first surface of the sensitive cell, and a support layer secured to the second surface of the sensitive cell and secured to the object. The functionalized object comprises at least two electrically conductive strips disposed on the first surface of the sensitive cell and on a surface of the object, each strip connecting an electrode to an electrical contact pad. A method is used for producing such a functionalized object.

A MEMS device includes a piezoelectric layer made of a piezoelectric single crystal, a first electrode on a first surface of the piezoelectric layer, and a first layer covering the first surface of the piezoelectric layer. At least a portion of the piezoelectric layer is included in a membrane portion. The first electrode is covered with the first layer and includes a recess. The piezoelectric layer includes a through hole that passes through the piezoelectric layer between a surface of the piezoelectric layer, which is opposite to the first direction, and the recess at a position corresponding to at least a portion of the first electrode.

A process for transferring a thin layer consisting of a first material to a support substrate consisting of a second material having a different thermal expansion coefficient, comprises providing a donor substrate composed of an assembly of a thick layer formed of the first material and of a handle substrate having a thermal expansion coefficient similar to that of the support substrate, and the donor substrate having a main face on the side of the thick laver; introducing light species into the thick layer to generate a plane of weakness therein and to define the thin layer between the plane of weakness and the main face of the donor substrate; assembling the main face of the donor substrate with a face of the support substrate; and detachment of the thin layer at the plane of weakness, the detachment comprising application of a heat treatment.

A cooling system employs at least one composite elastocaloric device. Each composite device has a first member with a first material and a second member with an elastocaloric material. The first material increases in size in response to an applied electric or magnetic field and returns to its prior size upon removal of the applied electric or magnetic field. The first and second members are mechanically coupled together such that the increase in size of the first material applies a stress to the elastocaloric material and the return of the first material to its prior size releases said stress, thereby causing the elastocaloric material to absorb heat.

A micromachined ultrasonic transducer (MUT) which comprises a first piezoelectric layer and a second piezoelectric layer. The first piezoelectric layer is disposed between a first electrode and a second electrode. The second piezoelectric layer is disposed between the second electrode and a third electrode. At least the first electrode has first and second ends along a first axis, one or more of which is defined by a radius of curvature R. A second axis normal to the first passes through a midpoint of the first axis. A half-width of the first electrode is defined by a length L measured from the midpoint, in the direction of the second axis, to an outer perimeter of the first electrode. A total width of the first electrode at its narrowest point along the first axis is at most 2L such that the first electrode has a concave shape. R/L, is greater than 1.

An ultrasound system, probe and method are provided. The ultrasound system includes a transducer with piezoelectric transducer elements polarized in a poling direction. A bipolar transmit circuit is configured to generate a transmit signal having first and second polarity segments. The first and second polarity segments have corresponding first and second peak amplitudes. A bias generator is configured to generate a bias signal in a direction of the poling direction. The bias signal is combined with the transmit signal to form a biased transmit signal that is shifted in the direction of the poling direction and still includes both of positive and negative voltages over a transmit cycle.

A nano-positioning system for fine and coarse nano-positioning including at least one actuator, wherein the at least one actuator includes a high Curie temperature material and wherein the nano-positioning system is configured to apply a voltage to the at least one actuator to generate fine and/or coarse motion by the at least one actuator. The nano-positioning system being a stand-alone system, a scanning probe microscope, or an attachment to an existing microscope configured to perform a method of creepless nano-positioning that includes positioning a probe relative to a first area of a substrate using coarse stepping and interacting with the first area of the substrate using fine motion after less than 60 seconds of the positioning the probe. The movement of the scanning probe microscope is actuated by a high Curie temperature piezoelectric material that limits and/or eliminates creep, hysteresis and aging.

An ultrasonic sensor includes a substrate, a platen and an acoustic stack disposed between the substrate and the platen, including at least one piezoelectric layer. The ultrasonic transducer exhibits a signal-to-noise ratio of at least 4 over a frequency range of at least 9 to 16 MHz.