This PDF file contains the front matter associated with SPIE Proceedings Volume 6885, including the Title Page, Copyright information, Table of Contents, Introduction, Conference Committee listing, and Plenary Paper.

Since the initial development of lasers in the 1960's, a longstanding dream has been to utilize these special intense radiation (light) sources to redirect the outcome of chemical reactions. In the ensuing years, much effort has gone into attempts at making this dream a reality. Emerging recent successful experiments derive from a confluence of ultrafast laser technology, control theory concepts, and suitable pattern recognition algorithms all drawn together to form adaptive machines. The adaptive machines are being used to manipulate chemical bonds, as well as a broad variety of other atomic and molecular dynamics phenomenon. These advances rest on the ability to delicately shape laser pulses so that they act as a special type of photonic reagents.

Today, nano-science provides an overwhelmingly large number of experimentally accessible ways to configure the spatial position of atoms, molecules, and other nanoscale components to form devices. The challenge is to find the best, most practical, configuration that yields a useful device function. In the presence of what will typically be an enormous non-convex search space, it is reasonable to assume that traditional ad-hoc design methods will miss many possible solutions. One approach to solving this difficult problem is to employ machine-based searches of configuration space that discover user-defined objective functions. Such an optimal design methodology aims to identify the best brokensymmetry spatial configuration of metal, semiconductor, and dielectric that produce a desired response. Hence, by harnessing a combination of modern compute power, adaptive algorithms, and realistic physical models, it should be possible to seek robust, manufacturable designs that meet previously unobtainable system specifications. Ultimately one can envision a methodology that simultaneously is capable of basic scientific discovery and engineering for technological applications.

Any scientific instrument, including an electrical amplifier, necessarily adds noise in the process of performing a measurement. As might be expected from knowledge of Heisenberg's uncertainty principle, quantum mechanics sets strict limits on how little noise a measurement can add. There is a great deal of current interest in performing measurements at the quantum limit on such systems as qubits and nanomechanical resonators. Here we introduce the notion of quantum limited electrical measurement, and discuss recent progress made toward this goal.

Heterodimerization between designed helix-loop-helix polypeptides was utilized in order to assemble gold nanoparticles on planar substrates. The peptides were designed to fold into four-helix bundles upon dimerization. A Cys-residue in the loop region was used to immobilize one of the complementary peptides on a maleimide containing SAM on planar gold substrates whereas the second peptide was immobilized directly on gold nanoparticles. Introducing the peptide decorated particles over a peptide functionalized surface resulted in particle assembly. Further, citrate stabilized particles were assembled on amino-silane modified glass and silicon substrates. By subsequently introducing peptides and gold nanoparticles, particle-peptide hybrid multi layers could be formed.

We present a microfluidic chemical/biological sensor based on dissolvable membranes incorporating gold nanoparticles. The presence of the target analyte in a fluidic sample being assayed dissolves the membrane, causing the change in its optical absorption. To enhance the contrast between the membrane and the fluidic sample, the membranes are chemically treated to exhibit strong absorption at certain wavelengths. Here, we use N,N'-cystaminebisacrylamide (CBA) cross-linked poly(acrylamide) (PAAm) membranes dissolved by a sample solution containing dithioerythritol (DTT) to demonstrate this approach. The dissolvable membrane incorporates gold nanoparticles to exhibit strong absorption at 572nm.

This paper reports the design, fabrication and measurements of a dual-reflective, single-crystal silicon based micromirror that can perform full circumferential scanning (FCS) for endoscopic optical coherence tomography (EOCT). In the proposed FCS-EOCT probe, two optical fibers are used to deliver light beams to either surface of the micromirror, which can rotate ±45° (or 90°) and thus a 180° optical scanning is obtained from each mirror surface, resulting in full circumferential scans. A novel surface- and bulk-combined micromachining process based on SOI wafers is developed for fabricating the dual reflective micromirror. The single-crystal-silicon device layer of SOI wafers is used for mirror flatness, and Al is coated on both sides for high reflectivity. With one light beam delivered to each mirror surface, full 360° scans have been observed. Other measured data include the resonant frequency: 328Hz, radius of curvatures: - 124 mm (front surface) and 127 mm (back surface), and the reflectances: 81.3% (front surface) and 79.0% (back surface).

We present the design and construction of a micro-display consisting of independently microfabricated light emitting diodes (LEDs) and silicon transistors on unconventional substrates such as flexible plastics. The fabrication process takes advantage of self-assembly to form the display. Silicon microcomponents and AlGaAs red LEDs were microfabricated and released to form a powder-like collection of parts. A plastic template containing binding sites was independently microfabricated. Each binding site on the template consisted of a well with a shape complementary to that of the released component. Self-assembly process was conducted in a fluidic medium to allow the microcomponents to assemble in proper receptor sites on the flexible template. We showed self-assembly of both LEDs and driving circuitry for display on plastic template. We got more than 90% yield for physically positioning the parts on template, with electrical connection yield of 62%.

We fabricate and experimentally characterize metal-semiconductor-metal (MSM) photodetectors with CNT film Schottky electrodes on n-type and p-type silicon substrates. We extract a Schottky barrier height of ~0.45 eV and ~0.51 eV for CNT films on n-type and p-type Si respectively. The extracted barrier height corresponds to a CNT film workfunction of 4.5-4.7 eV, which is within the range of the previously reported workfunction values for individual CNTs. Furthermore, we find that while at temperatures above 240°K thermionic emission is the dominant transport mechanism, at lower temperatures tunneling begins to dominate. We also characterize the photoresponse of the CNT film-Si MSM photodetector by illuminating the samples with a 633 nm HeNe laser. We observe that while the photocurrent of the CNT film MSM devices is similar to that of the Ti/Au control samples at high biases, their lower dark current results in a higher photo-to-dark current ratio relative to the control devices. We explain these observations by comparing the two interfaces. This work opens up the possibility of integrating CNT films as transparent and conductive Schottky electrodes in conventional semiconductor electronic and optoelectronic devices.

A reduced order thermal model of a one-dimensional (1D) electrothermally actuated micromirror device is reported. Thermal bimorphs with integrated Pt resistors are used for generating the angular rotation. Neglecting the temperature variation perpendicular to the length of the bimorphs, a 2D finite element thermal model with 4647 nodes is built. The accuracy of the model is verified by comparing the simulation results with thermal imaging data. Using a Krylov subspace based algorithm, a reduced order model is extracted from the finite element model. Results obtained from a reduced model with order ≥ 5 agree well with finite element results. Hence, a reduced order thermal model that saves computation time and resources without compromising the computation accuracy has been demonstrated.

The applicability of an existing compact model that captures the effect of rarefaction and inertia is studied in this paper. In order to ascertain the accuracy of the model, we take two different configurations of a torsional MEMS structure from the literature which operate under different frequencies and have different air-gap thicknesses. For the structure with large air-gap and low operating frequency, the analytical model based on the equivalent length captures the effect well under the continuum, slip, transition and the molecular regimes. On the other hand, for the structures with high operating frequencies but low air-gap thickness, the analytical model breaks down in the transition regime.

Submicron cantilever structures have been demonstrated to be extremely versatile sensors and have potential applications in physics, chemistry and biology. The basic principle in submicron cantilever sensors is the measurement of the resonance frequency shift due to the added mass of the molecules bound to the cantilever surface. This paper presents a theoretical model to predict the resonance frequency shift due to molecular adsorption on submicron cantilevers. The influence of the mechanical properties of the adsorbed molecules bound to the upper and lower surface on the resonance frequency has been studied. For various materials, the ratio between the thicknesses of the adsorbed layer and the cantilever where either stiffness or added mass is dominant will be determined. The critical ratio (which contribution of effect cancel each others) between the thickness of the adsorbed layer and the cantilever and ratio between stiffness and density of adsorbed layer and cantilever have been determined. The calculations show the added mass and stiffness how contribute to the resonant behavior. This model gives insight into the decoupling of both opposite effects and is expected to be useful for the optimal design of resonators with high sensitivity to molecular adsorption based on either stiffness or mass effects.

Nanowires of a diameter less than 50nm have been predicted to exhibit a higher thermoelectric figure of merit in comparison to their bulk equivalent. In order to experimentally measure the thermoelectric power in nanowires it is necessary to design and fabricate a measurement platform that is ideally matched in thermal and physical size and capable of testing a large number of individual nanowires in a high throughput manner. In this paper we present the design, fabrication, and characterization of a MEMS thermoelectric workbench with a high density of testing locations. Characteristic measurements of the thermoelectric power of Au nanowires are presented as demonstration of the workbench functionality.

Energy scavenging is a technology that derives required microwatt level power to drive electronics from ambient heat, light, radio, or vibration, that is otherwise wasted. In this study, we have investigated the circuit optimization strategy for vibration-based piezoelectric energy scavenging systems that supply the electric power to wireless sensors and electronics for ubiquitous sensor networks. In this paper, we assert that not only the mechanical to electrical energy conversion efficiency, but also the speed of energy storage is important in designing and evaluation of energy scavenging system, since the energy scavenging system with higher speed of energy storage has faster start up response to the mechanical input and can supply required power more frequently. Particularly in case of piezoelectric micropower generator, we show that the low reverse leakage current characteristic rather than the low forward voltage drop of the rectifying diodes is much more beneficial to improve conversion efficiency and that the storage capacitor should be as small as possible to reduce the time to store required amount of energy. Experimental and PSPICE results show that, when ultra-low leakage current diodes are adopted for a bridge rectifier, the mechanical-to-electrical energy conversion efficiency is doubled or more in some cases, and the charging speed is increased by 20%, compared to the circuit that adopts Schottky diodes. It is also found that, compared to the circuit with larger storage capacitor, the circuit with smaller storage capacitor requires shorter time to store the same amount of energy and can drive voltage regulator more frequently. This study suggests that low reverse leakage diode and small storage capacitor should be used to build efficient high performance piezoelectric energy scavenging systems for ubiquitous sensor networks.