Enhanced Resolution of Poly-(Methyl Methacrylate) Electron Resist by Thermal Processing

Granular nanostructure of electron beam resist had limited the ultimate resolution of electron beam lithography. We report a thermal process to achieve a uniform and homogeneous amorphous thin film of poly methyl methacrylate electron resist. This thermal process consists of a short time-high temperature backing process in addition to precisely optimized development process conditions. Using this novel process, we patterned arrays of holes in a metal film with diameter smaller than 5nm. In addition, line edge roughness and surface roughness of the resist reduced to 1nm and 100pm respectively.Comment: 8 pages, 4 figure

Power extraction from ambient vibration

Autonomous devices such as sensors for personal area networks need a long battery lifetime in a small volume. The battery size can be reduced by incorporating micro-power generators based on ambient energy. This paper describes a new approach to the conversion of mechanical to electrical energy, based on charge transportation between two parallel capacitors. The polarization of the device is handled by an electret. A largesignal model was developed, allowing simulations of the behavior of any circuit based on this generator for any mechanical input signal. A small-signal model was derived in order to quantify the output power as a function of the design parameters. A layout was made based on a standard SOI-technology, available in a MPW. With this layout it is possible to generate 100 mW at 1200 Hz

Self-assembled hexagonal double fishnets as negative index materials

We show experimentally the successful use of colloidal lithography for the fabrication of negative index metamaterials in the near-infrared wavelength range. In particular, we investigated a specific implementation of the widely studied double fishnet metamaterials, consisting of a gold-silica-gold layer stack perforated by a hexagonal array of round holes. Tuning of the hole diameter allows us to tailor these self-assembled metamaterials both as single- ({\epsilon} < 0) and double ({\epsilon} < 0 and {\mu} < 0) negative metamaterials

Multifunctional Nanomechanical Systems via Tunably Coupled Piezoelectric Actuation

Efficient actuation is crucial to obtaining optimal performance from nanoelectromechanical systems (NEMS). We employed epitaxial piezoelectric semiconductors to obtain efficient and fully integrated NEMS actuation, which is based on exploitation of the interaction between piezoelectric strain and built-in charge depletion. The underlying actuation mechanism in these depletion-mediated NEMS becomes important only for devices with dimensions approaching semiconductor depletion lengths. The induced actuation forces are controlled electrically, and resonant excitation approaching single-electron efficiency is demonstrated. The fundamental electromechanical coupling itself can be programmed by heterostructure band engineering, externally controllable charge depletion, and crystallographic orientation. These attributes are combined to realize a prototype, mechanically based, exclusive-or logic element

Local solid-state modification of nanopore surface charges

The last decade, nanopores have emerged as a new and interesting tool for the study of biological macromolecules like proteins and DNA. While biological pores, especially alpha-hemolysin, have been promising for the detection of DNA, their poor chemical stability limits their use. For this reason, researchers are trying to mimic their behaviour using more stable, solid-state nanopores. The most successful tools to fabricate such nanopores use high energy electron or ions beams to drill or reshape holes in very thin membranes. While the resolution of these methods can be very good, they require tools that are not commonly available and tend to damage and charge the nanopore surface. In this work, we show nanopores that have been fabricated using standard micromachning techniques together with EBID, and present a simple model that is used to estimate the surface charge. The results show that EBID with a silicon oxide precursor can be used to tune the nanopore surface and that the surface charge is stable over a wide range of concentrations.Comment: 10 pages, 6 figure

A novel strategy for the comprehensive analysis of the biomolecular composition of isolated plasma membranes

A methodology for rapid, high-purity isolation of plasma membranes using superparamagnetic nanoparticles is described. The method is illustrated with high-resolution proteomic, glycomic and lipidomic analyses of presenilin-deficient cells

Boosting the Figure Of Merit of LSPR-based refractive index sensing by phase-sensitive measurements

Localized surface plasmon resonances possess very interesting properties for a wide variety of sensing applications. In many of the existing applications only the intensity of the reflected or transmitted signals is taken into account, while the phase information is ignored. At the center frequency of a (localized) surface plasmon resonance, the electron cloud makes the transition between in- and out-of-phase oscillation with respect to the incident wave. Here we show that this information can experimentally be extracted by performing phase-sensitive measurements, which result in linewidths that are almost one order of magnitude smaller than those for intensity based measurements. As this phase transition is an intrinsic property of a plasmon resonance, this opens up many possibilities for boosting the figure of merit (FOM) of refractive index sensing by taking into account the phase of the plasmon resonance. We experimentally investigated this for two model systems: randomly distributed gold nanodisks and gold nanorings on top of a continuous gold layer and a dielectric spacer and observed FOM values up to 8.3 and 16.5 for the respective nanoparticles

Method for Flow Measurement in Microfluidic Channels Based on Electrical Impedance Spectroscopy

We have developed and characterized two novel micro flow sensors based on measuring the electrical impedance of the interface between the flowing liquid and metallic electrodes embedded on the channel walls. These flow sensors are very simple to fabricate and use, are extremely compact and can easily be integrated into most microfluidic systems. One of these devices is a micropore with two tantalum/platinum electrodes on its edges; the other is a micro channel with two tantalum /platinum electrodes placed perpendicular to the channel on its walls. In both sensors the flow rate is measured via the electrical impedance between the two metallic electrodes, which is the impedance of two metal-liquid junctions in series. The dependency of the metal-liquid junction impedance on the flow rate of the liquid has been studied. The effects of different parameters on the sensor's outputs and its noise behavior are investigated. Design guidelines are extracted and applied to achieve highly sensitive micro flow sensors with low noise.Comment: 11 pages, 7 figure