An optical device includes a gallium and nitrogen containing substrate comprising a surface region configured in a (20-2-1) orientation, a (30-3-1) orientation, or a (30-31) orientation, within +/−10 degrees toward c-plane and/or a-plane from the orientation. Optical devices having quantum well regions overly the surface region are also disclosed.

A liquid discharging head includes a pressure chamber partitioning portion that includes a plurality of partitioning walls that partition a pressure chamber in which a pressure to discharge a liquid is applied to the liquid, a diaphragm that includes a wall surface that faces the pressure chamber, The pressure chamber is located between the partitioning walls in a second direction. The wall surface of the diaphragm includes a first portion at a first position, and a second portion. A position of the second portion in the first direction is on an opposite side in the first direction with respect to a position of the first portion in the first direction.

An oscillator frequency modulation method includes: providing a piezoelectric material having a surface and an interior; and performing a pattern process on the piezoelectric material by a laser. A patterned processing zone is formed on the surface and/or in the interior of the piezoelectric material. The pattern process may be a material removal and/or a material modification. Therefore, without changing the appearance of the piezoelectric material, the pattern process on the piezoelectric material through the laser can accurately adjust the frequency of the oscillator and block unnecessary mode at the same time. An oscillator piezoelectric structure with frequency modulation is also provided.

A diaphragm for a piezoelectric micromachined ultrasonic transducer (PMUT) is presented having resonance frequency and bandwidth characteristics which are decoupled from one another into independent variables. Portions of at least the piezoelectric material layer and backside electrode layer are removed in a selected pattern to form structures, such as ribs, in the diaphragm which retains stiffness while reducing overall mass. The patterned structure can be formed by additive, or subtractive, fabrication processes.

A diaphragm for a piezoelectric micromachined ultrasonic transducer (PMUT) is presented having resonance frequency and bandwidth characteristics which are decoupled from one another into independent variables. Portions of at least the piezoelectric material layer and backside electrode layer are removed in a selected pattern to form structures, such as ribs, in the diaphragm which retains stiffness while reducing overall mass. The patterned structure can be formed by additive, or subtractive, fabrication processes.

A piezoelectric element includes a first electrode layer, a piezoelectric layer, and a second electrode layer. The first electrode layer, the piezoelectric layer, and the second electrode layer are stacked in sequence on one another. The first electrode layer has a first part overlapping the piezoelectric layer in a plan view, and a second part at least partially separated from the first part and not overlapping the piezoelectric layer in the plan view. The second electrode layer has a third part overlapping the piezoelectric layer in the plan view, and a fourth part separated from the third part. The fourth part is in contact with the first part and the second part.

A piezoelectric element includes a first electrode layer, a piezoelectric layer, and a second electrode layer. The first electrode layer, the piezoelectric layer, and the second electrode layer are stacked in sequence on one another. The first electrode layer has a first part overlapping the piezoelectric layer in a plan view, and a second part at least partially separated from the first part and not overlapping the piezoelectric layer in the plan view. The second electrode layer has a third part overlapping the piezoelectric layer in the plan view, and a fourth part separated from the third part. The fourth part is in contact with the first part and the second part.

Several types of piezoelectric MEMS vibration energy harvesters are described herein as well as methods of fabricating the vibration energy harvesters. The vibration energy harvesters generally comprise a serpentine structure having a central longitudinal axis; a piezoelectric film deposited on a surface of the serpentine structure; a central mass located at a mid-portion of the central longitudinal axis; two lateral masses positioned at opposing corners of the serpentine structure; anchor points at two other opposing corners of the serpentine structure; and upper and lower electrode layers. The energy harvesters have a 180 degree rotational symmetry about the central mass and when the serpentine structure experiences a strain, the piezoelectric film generates a voltage. The geometry of the energy harvesters allows for lower frequency and wider bandwidth operation as well as higher power density.

Several types of piezoelectric MEMS vibration energy harvesters are described herein as well as methods of fabricating the vibration energy harvesters. The vibration energy harvesters generally comprise a serpentine structure having a central longitudinal axis; a piezoelectric film deposited on a surface of the serpentine structure; a central mass located at a mid-portion of the central longitudinal axis; two lateral masses positioned at opposing corners of the serpentine structure; anchor points at two other opposing corners of the serpentine structure; and upper and lower electrode layers. The energy harvesters have a 180 degree rotational symmetry about the central mass and when the serpentine structure experiences a strain, the piezoelectric film generates a voltage. The geometry of the energy harvesters allows for lower frequency and wider bandwidth operation as well as higher power density.

Piezoelectric devices having small dimensions and which can operate at high frequencies with high penetration depths for a given applied voltage are described. The devices may be well suited for integration into medical devices, such as intravascular ultrasound (IVUS) catheters, to provide high resolution ultrasound images.