Air-coupled piezoelectric micromachined ultrasound transducer arrays, operating at ~190 kHz, have been fabricated utilizing an aluminum nitride piezoelectric layer. Improved fabrication processes have reduced the frequency variation seen in our previous work with single transducers resulting in arrays of transducers with resonant frequencies (fn) that match within the fractional half-power band...

The electronic properties of heterojunction electron gases formed in GaN/AlGaN core/shell nanowires with hexagonal and triangular cross sections are studied theoretically. We show that at nanoscale dimensions, the nonpolar hexagonal system exhibits degenerate quasi-one-dimensional electron gases at the hexagon corners, which transition to a core-centered electron gas at lower doping. In contras...

Numerous technical advances in the area of polymer light emitting diodes (PLEDs) have been made since their discovery in 1990 by Friend et al at Cambridge University . PLEDs are derivatives from the more commonly known LED (light emitting diode) devices. LEDs are solid-state semiconductor devices that convert electrical energy into light. They are typically used as indicator lights and numeric ...

Aluminum alloys such as Al 5083 have primary potential for lightweight structural application in automotive and aerospace industries. This paper addresses the mechanical and tribological properties and corrosion resistance of chromium nitride coatings deposited on Al 5083 that can be used for development of applications of aluminum 5083 alloy. The CrN coatings of 1 μm thickness were deposited b...

The shortest-wavelength color of light that is visible to the human eye is violet. As shown in Fig. 1, light with wavelengths shorter than 400 nm is called ultraviolet (UV) light: that from 300 to 400 nm is called near-UV light, that from 200 to 300 nm is called deep-UV light, and that shorter than 200 nm is called vacuum-UV light. Since vacuum-UV is absorbed by air, deep-UV light is the shorte...

The cut-then-stack paradigm of computer-aided manufacturing of laminated engineering materials (CAM-LEM) offers choice of feedstock material, ease of handling finely divided (and therefore sinterable) powders, and the ability to mix materials. This combination of features was exploited to process fluidic devices. CAM-LEM processing was used to render the Part in aluminum oxide, silicon nitride,...