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The present work focuses on the plasma deposition of fluorocarbon (FC) films on surfaces and the electrostatic control of their wettability (electrowetting). Such films can be employed for actuation of fluid transport in microfluidic devices, when deposited over patterned electrodes. Here, the deposition was performed using C4F8 and the plasma parameters that permit the creation of films with optimized properties desirable for electrowetting were established. The wettability of the plasma-deposited surfaces was characterized by means of contact angle measurements (in the static and dynamic mode). The thickness of the deposited films was probed in situ by means of spectroscopic ellipsometry, while the surface roughness was provided by atomic force microscopy. These plasma-deposited FC films in combination with silicon nitride, a material of high dielectric constant, were used to create a dielectric structure that requires reduced voltages for successful electrowetting. Electrowetting experiments using protein solutions were conducted on such optimized dielectric structures and were compared with similar structures bearing commercial spin-coated Teflon® amorphous fluoropolymer (AF) film as the hydrophobic top layer. Our results show that plasma-deposited FC films have desirable electrowetting behavior and minimal protein adsorption, a requirement for successful transport of biological solutions in “digital” microfluidics. [ABSTRACT FROM AUTHOR]

A method is proposed for a thorough analysis of rear point contact solar cell structures. The method is based on the numerical solution through Fast fourier transform of the minority and majority carrier transport equations in three dimensions in the base of the cell. Their illuminated current-voltage characteristics are simulated and the series resistance of the cell is calculated. Results are presented which show the influence of the rear contact size and the majority transport in the base to the solar cell performance. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Provides information on a study regarding the carrier lifetimes of highly injected silicon. Observation on recombination lifetime of high-injection conditions of diodes; Discussion of the processes of electroluminescence signal; Analysis of carrier plasma density.

Presents a mathematical analysis and parameter-extraction process for a new characterization method. Functions of the method; Derivation of exact closed-form solutions associated with two-dimensional devices; Description of the simultaneous extraction of minority-carrier transport parameters.

Focuses on a study that investigated the use of computer simulation and analytical models for the time-of-flight experiment in amorphous silicon thin films. Numerical results and physical interpretation; Description of analytical models; Conclusions.

Presents a series of analytical and equivalent-circuit models based on numerical solutions for hydrogenated amorphous silicon solar cells. Details on the numerical modeling; Interpretation of the numerical results; Analytical solutions for uniformly absorbed light.

Presents information on a study which determined the several parameters of three-dimensional semiconductor devices such as diodes, transistors and solar cells without solving the actual boundary-value problem. Description of the devices; Basic assumptions and equations; Transit time of a shallow junction diode.

Examines the decay of excess carriers induced in a semiconductor sample. Solution of the continuity equation in planar symmetry cases; Discussion on the photoluminescence decay response.

Abstract: A methodology for the prediction of chemocapacitor response due to the sorption of analyte without the need for fabrication of the actual devices is introduced. The methodology is based on experimental measurement of volume fraction due to sorption of the analyte through reflectance measurements and electromagnetic modeling for the InterDigitated Electrode (IDE) capacitor. The volume fraction and the capacitance of the device are coupled through the use of Clausius-Mossotti equation for the calculation of dielectric constant of sorbed polymeric film resulting in the prediction of the capacitance change due to the sorption of the analyte. [Copyright &y& Elsevier]

Abstract: Effective immobilization of biomolecules at transducer interfaces plays a crucial role in biosensors development. In this work, we compared several silicon nitride (Si3N4) surface silanization methods in terms of efficient biomolecule immobilization either through physical adsorption or covalent binding. Two silanizing agents, namely 3- aminopropyltriethoxysilane (APTES) and 3-glycidyloxypropyltrimethoxysilane (GOPTS), were employed. It was found that silanization with GOPTS provided slightly higher protein immobilization capacity and homogeneity and lower non-specific binding as compared to APTES modification. Therefore, it could be employed for the effective functionalization of Si3N4 waveguides for biosensing applications. [Copyright &y& Elsevier]

Binding of biomolecules in real-time is studied by white light reflectance spectroscopy (WLRS). The experimental apparatus consists of a WLRS setup and a microfluidic channel for the supply of the biomolecules solutions placed above the sample on which the biomolecular interactions take place. Using this setup, it is possible to monitor in real-time the biomolecular film thickness changes during the binding of biomolecules on a properly treated surface. The sample is a silicon wafer with a thick thermally grown silicon dioxide (∼1044 nm) and a thin (∼35 nm) polymer layer. The proposed methodology has been applied for the monitoring of streptavidin binding to surface-immobilised biotinylated protein. The biomolecular interactions are monitored as shifts of the wavelength where constructive interference is observed. The proposed methodology provides a simple, fast, low cost approach for a label-free monitoring of biomolecular interactions. [ABSTRACT FROM AUTHOR]

Focuses on a study which described a pixel chip for an asynchronous architecture. Circuit description; Design measurements; Structural description of pixels.

Presents information on a study which developed and evaluated a system consisting of both the readout electronics and the detecting element integrated on the same substrate. Pixel electronics; X-ray spectroscopy measurements; Conclusion.

Presents information on study which proposed a two-dimensional high counting rate detector based on strip geometry, preamplifying NMOS transistors and resisitive charge division. Noise performance of simulations; Description of the detector; Conclusion.

Presents information on a study which developed a complementary metal oxide semiconductor charge sensitive readout chain suitable for pixel applications. Capability of the system; Details on charge-shaper-voltage amplifier; Analysis of self-switched approach; Measurements; Conclusions.

An automated method for creating micron-sized patterns of different proteins is described. Unlike other methods, the process requires no masks, photochemichal reagents, or alignment. The basic tools are a motorized x–y stage, a pneumatic drive, and a micromachined silicon chip with an array of micron scale pyramids. Upon pressing the chip on a plastic slide, inverted pyramids are created on the polymer surface, exposing areas that have no previous coating and can adsorb proteins. The method is suitable for the fast and inexpensive fabrication of dense arrays of different proteins on appropriate substrates. [ABSTRACT FROM AUTHOR]