Spin-Wave Optics in YIG Realized by Ion-Beam Irradiation.

Direct focused-ion-beam writing is presented as an enabling technology for realizing functional spin-wave devices of high complexity, and demonstrate its potential by optically-inspired designs. It is shown that ion-beam irradiation changes the characteristics of yttrium iron garnet films on a submicron scale in a highly controlled way, allowing one to engineer the magnonic index of refraction adapted to desired applications. This technique does not physically remove material, and allows rapid fabrication of high-quality architectures of modified magnetization in magnonic media with minimal edge damage (compared to more common removal techniques such as etching or milling).

Efficient electromagnetic transducers for spin-wave devices.

This paper presents a system-level efficiency analysis, a rapid design methodology, and a numerical demonstration of efficient sub-micron, spin-wave transducers in a microwave system. Applications such as Boolean spintronics, analog spin-wave-computing, and magnetic microwave circuits are expected to benefit from this analysis and design approach. These applications have the potential to provide a low-power, magnetic paradigm alternative to modern electronic systems, but they have been stymied by a limited understanding of the microwave, system-level design for spin-wave circuits.

Nanoantenna-based ultrafast thermoelectric long-wave infrared detectors.

We investigate the generation of electrical signals by suspended thermoelectrically coupled nanoantennas (TECNAs) above a quasi-spherical reflector cavity in response to rapidly changing long-wave infrared radiation. These sensors use a resonant nanoantenna to couple the IR energy to a nanoscale thermocouple. They are positioned over a cavity, etched into the Si substrate, that provides thermal isolation and is designed as an optical element to focus the IR radiation to the antenna.

Cavity-Backed Antenna-Coupled Nanothermocouples.

This paper reports a two-orders-of-magnitude improvement in the sensitivity of antenna-coupled nanothermocouple (ACNTC) infrared detectors. The electrical signal generated by on-chip ACNTCs results from the temperature difference between a resonant antenna locally heated by infrared radiation and the substrate. A cavity etched under the antenna provides two benefits.

Do SE(II) electrons really degrade SEM image quality?

Generally, in scanning electron microscopy (SEM) imaging, it is desirable that a high-resolution image be composed mainly of those secondary electrons (SEs) generated by the primary electron beam, denoted SE(I) . However, in conventional SEM imaging, other, often unwanted, signal components consisting of backscattered electrons (BSEs), and their associated SEs, denoted SE(II) , are present; these signal components contribute a random background signal that degrades contrast, and therefore signal-to-noise ratio and resolution. Ideally, the highest resolution SEM image would consist only of the SE(I) component.

Direct control of electron transfer to the surface-CO bond on a Pt/TiO2 catalytic diode.

We study CO adsorption on a multilayer catalytic diode in which electron transfer at the metal-semiconductor (Pt/TiO(2)) junction is controlled by an applied external voltage. The multilayer diode structure enhances infrared absorption signals from CO molecules adsorbed on the small area Pt surface. We find that the diode behaves like a Schottky junction and that changes in electron transfer at the junction are directly correlated with reversible shifts in the vibrational frequency of adsorbed CO.

Guided deposition of individual DNA nanostructures on silicon substrates.

We demonstrate immobilization of DNA nanostructures (37 nm x 8 nm) on silicon by a combination of "top-down" fabrication and "bottom-up" self-assembly. Anchor lines and pads were defined using electron beam lithography and a cationic molecular monolayer. Individual DNA nanostructures bind in 85% yield onto the anchor pads and can be washed and imaged in air.

Deposition of DNA rafts on cationic SAMs on silicon [100].

We demonstrate a guided self-assembly approach to the fabrication of DNA nanostructures on silicon substrates. DNA oligonucleotides self-assemble into "rafts" 8 x 37 x 2 nm in size. The rafts bind to cationic SAMs on silicon wafers.

Bio-inspired nano-sensor-enhanced CNN visual computer.

Nanotechnology opens new ways to utilize recent discoveries in biological image processing by translating the underlying functional concepts into the design of CNN (cellular neural/nonlinear network)-based systems incorporating nanoelectronic devices. There is a natural intersection joining studies of retinal processing, spatio-temporal nonlinear dynamics embodied in CNN, and the possibility of miniaturizing the technology through nanotechnology. This intersection serves as the springboard for our multidisciplinary project.

A liftoff technique for molecular nanopatterning.

For quantum-dot cellular automata molecular electronic devices, one of the fundamental tasks is to arrange the molecules on a surface in a controlled manner. In this report, we discuss a molecular lift off technique to form nanopatterns toward the development of molecular circuits. In our molecular lift off technique, we use electron beam lithography to form nano-trenches on a polymethylmethacrylate (PMMA) film on a SiO2 wafer.

A two-stage shift register for clocked Quantum-Dot Cellular Automata.

Quantum-Dot Cellular Automata (QCA) is a computational scheme utilizing the position of interacting single electrons within arrays of quantum dots ("cells") to encode and process binary information. Clocked QCA architectures can provide power gain, logic level restoration, and memory features. Using arrays of micron-sized metal dots, we experimentally demonstrate operation of a QCA latch-inverter and a two-stage shift register.