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Rapid progress in materials science and electrical engineering has led to the development of miniature electronic platforms that have devices and components as small as the main components of live cells. These developments open up an exciting possibility of building integrated systems in which electronic and biological components function side-by-side. However, to realize this vision of bionanoelectronics, researchers need to overcome a number of challenges ranging from materials incompatibility to drastically different operation modes. Fortunately, recent developments in biosensing, and device-level and tissue-level integration with nanomaterials have started to address these challenges.

In this study, a new method coupling laser irradiation into a dual-beam scanning electron microscope(SEM) and focused-ion-beam(FIB) system is developed. By using a lensed fiber, pulsed laser illumination could be successfully delivered onto the sample under SEM imaging, providing in situ monitoring for laser material processing applications including local modification of micro-/nanostructures and laser-assisted chemical vapor deposition. In situ characterization of the laser-induced features by high resolution SEM imaging and energy dispersive x-ray spectrometry was successfully carried out. Furthermore, in situ repair of a contaminated lensed fiber probe during laser-assisted chemical vapor deposition was demonstrated via FIB milling. The results demonstrate the full compatibility of the lensed fiber apparatus with the dual-beam apparatus without disturbing the original functions of the system. The combination of guided laser radiation with SEM and FIB instruments offers a powerful capability for in situ monitoring of multilevel laser-based micro- and nanoscale material processing.

Evaluation of the radiative component in heat-transfer problems is often difficult and expensive. To address this problem, in the recent past, attention has been focused on improving the performance of various approximate methods. Computational efficiency of any method depends to a great extent on the quadrature schemes that are used to compute the source term and heat flux. The discrete ordinate method (DOM) is one of the oldest and still the most widely used methods. To make this method computationally more attractive, various types of quadrature schemes have been suggested over the years. In the present work, a new quadrature scheme has been suggested. The new scheme is a simple one and does not involve complicated mathematics for determination of direction cosines and weights. It satisfies all the required moments. To test the suitability of the new scheme, four benchmark problems were considered. In all cases, the proposed quadrature scheme was found to give accurate results.

Biological molecules perform a sophisticated array of transport and signaling functions that rival anything that the modern electronics industry can create. Incorporating such building blocks into nanoelectronic devices could enable new generations of electronic circuits that use biomimetics to perform complicated tasks. Such types of circuits could ultimately blur the interface between living biological organisms and synthetic structures. Our laboratory has recently developed a versatile and flexible platform for integrating ion channels and pumps into single-walled carbon nanotube (SWNT) and silicon nanowire (SiNW) transistor devices, in which membrane proteins are embedded in a lipid bilayer shell covering the nanotube or nanowire component. In this chapter, we provide details for the fabrication of these devices and outline procedures for incorporating biological molecules into them. In addition, we also provide several examples of the use of these devices to couple biological transport to electronic signaling.

Biological molecules perform a sophisticated array of transport and signaling functions that rival anything that the modern electronics industry can create. Incorporating such building blocks into nanoelectronic devices could enable new generations of electronic circuits that use biomimetics to perform complicated tasks. Such types of circuits could ultimately blur the interface between living biological organisms and synthetic structures. Our laboratory has recently developed a versatile and flexible platform for integrating ion channels and pumps into single-walled carbon nanotube (SWNT) and silicon nanowire (SiNW) transistor devices, in which membrane proteins are embedded in a lipid bilayer shell covering the nanotube or nanowire component. In this chapter, we provide details for the fabrication of these devices and outline procedures for incorporating biological molecules into them. In addition, we also provide several examples of the use of these devices to couple biological transport to electronic signaling.

Modern means of communication rely on electric fields and currents to carry the flow of information. In contrast, biological systems follow a different paradigm that uses ion gradients and currents, flows of small molecules, and membrane electric potentials. Living organisms use a sophisticated arsenal of membrane receptors, channels, and pumps to control signal transduction to a degree that is unmatched by manmade devices. Electronic circuits that use such biological components could achieve drastically increased functionality; however, this approach requires nearly seamless integration of biological and manmade structures. We present a versatile hybrid platform for such integration that uses shielded nanowires (NWs) that are coated with a continuous lipid bilayer. We show that when shielded silicon NW transistors incorporate transmembrane peptide pores gramicidin A and alamethicin in the lipid bilayer they can achieve ionic to electronic signal transduction by using voltage-gated or chemically gated ion transport through the membrane pores.

Nanoscale electrodes based on one-dimensional inorganic conductors could possess significant advantages for electrochemical measurements over their macroscopic counterparts in a variety of electrochemical applications. We show that the efficiency of the electrodes constructed of individual highly doped silicon nanowires greatly exceeds the efficiency of flat Si electrodes. Modification of the surfaces of the nanowire electrodes with phospholipid bilayers produces an efficient biocompatible barrier to transport of the solution redox species to the nanoelectrode surface. Incorporating functional alpha-hemolysin protein pores in the lipid bilayer results in a partial recovery of the Faradic current due to the specific transport through the protein pore. These assemblies represent a robust and versatile platform for building a new generation of highly specific biosensors and nano/bioelectronic devices.

In most Si nanowire (NW) applications, Si oxide provides insulation or a medium of controlled electron tunneling. This work revealed both similarities and differences in the dielectric properties of NW oxide compared with that grown on wafers. The interface barrier to electron transit from the semiconductor to the dielectric and the threshold electric field for current flow are quite similar to those in the planar geometry. This is not true for the lowest currents measured which are not uniformly distributed, indicating variations of trap density in the gap of NW oxide.

Si nanowires (NWs) are being considered and tested for a range of exciting applications in nanoelectronics, including memory, logic gates, single electron transistors [1], optoelectronic devices [2] and sensors [3]. Particularly relevant to this work are non-volatile memory applications, such as Silicon Nanowire based memory on Semiconductor-Oxide-Nitride, SONOS [4], for which tunneling through the dielectric is part of normal operation. The specifications and reliability of these devices relate to the surface structure of the NWs and to the properties of the oxide sheath which is called to play the role of gate dielectric [5, 6]. Structures such as wraparound gate transistors [7] or core-shell heterostructures [8] require good control of the wire surface, in order to achieve uniform cross section and to minimize carrier scattering at rough interfaces. Equally important are the charge transport properties of the oxide which may be affected by surface irregularities. Current through planar gates grown on Si wafers and, particularly, the effect of Stress Induced Leakage Current (SILC) have been the subject of a vast body of experimental research and models proposed [9-11]. On the other hand, little is known about SILC and related phenomena in Si NW based MOS devices. As pointed out by Vogel [12], these are likely to continue controlling future transistors fabricated by technologies beyond microlithography on wafers and it is important to find new and complementary ways for their characterization.Si nanowires (NWs) are being considered and tested for a range of exciting applications in nanoelectronics, including memory, logic gates, single electron transistors [1], optoelectronic devices [2] and sensors [3]. Particularly relevant to this work are non-volatile memory applications, such as Silicon Nanowire based memory on Semiconductor-Oxide-Nitride, SONOS [4], for which tunneling through the dielectric is part of normal operation. The specifications and reliability of these devices relate to the surface structure of the NWs and to the properties of the oxide sheath which is called to play the role of gate dielectric [5, 6]. Structures such as wraparound gate transistors [7] or core-shell heterostructures [8] require good control of the wire surface, in order to achieve uniform cross section and to minimize carrier scattering at rough interfaces. Equally important are the charge transport properties of the oxide which may be affected by surface irregularities. Current through planar gates grown on S...

We report a rapid and low temperature process for fabricating composite TiO2 electrodes for dye-sensitized solar cells on glass and plastics by in tandem spray deposition and laser annealing. A homogenized KrF excimer laser beam (248 nm) was used to layer-by-layer anneal spray deposited TiO2 nanoparticles. The produced TiO2 film is crack free and contains small particles (30 nm) mixed with different fractions of larger particles (100–200 nm) controlled by the applied laser fluence. Laser annealed double-layered structure is demonstrated for both doctor-blade deposited and spray-deposited electrodes and performance enhancement can be observed. The highest demonstrated all-laser-annealed cells utilizing ruthenium dye and liquid electrolyte showed power conversion efficiency of ∼3.8% under simulated illumination of 100 mW/cm2.

Organic material direct writing was demonstrated based on nanomaterial enabled laser transfer (NELT). Through proper nanoparticle size and type, and the laser wavelength choice, a single laser pulse could transfer well defined and arbitrarily shaped tris-(8-hydroxyquinoline)Al patterns ranging from several microns to millimeter size. The unique properties of nanomaterials allow the laser induced forward transfer process to be effected at irradiation energies and temperatures lower than commonly used. The technique may be well suited for the mass production of temperature sensitive devices.Organic material direct writing was demonstrated based on nanomaterial enabled laser transfer (NELT). Through proper nanoparticle size and type, and the laser wavelength choice, a single laser pulse could transfer well defined and arbitrarily shaped tris-(8-hydroxyquinoline)Al patterns ranging from several microns to millimeter size. The unique properties of nanomaterials allow the laser induced forward transfer process to be effected at irradiation energies and temperatures lower than commonly used. The technique may be well suited for the mass production of temperature sensitive devices.

We report postgrowth doping of silicon nanowires (SiNWs) through ion implantation and subsequent annealing with nanosecond pulsed laser light. The green laser annealing process allows for polarization selective localized heating and enables highly efficient activation of implanted boron and arsenic in the SiNWs as revealed by electrical resistivity measurements. Transistor devices fabricated by this technique show reduced parasitic series resistance and higher drive currents making the process suitable for fabrication of high-performance NW based electronics on glass and plastics.

Short pulsed laser induced single acoustic wave generation, propagation, interaction with rigid structures, and focusing in water are experimentally and numerically studied. A large area short duration single plane acoustic wave was generated by the thermoelastic interaction of a homogenized nanosecond pulsed laser beam with a liquid-solid interface and propagated at the speed of sound in water. Laser flash schlieren photography was used to visualize the transient interaction of the plane acoustic wave with various submerged rigid structures [(a) a single block, (b) double blocks, (c) 33° tilted single block, and (d) concave cylindrical acoustic lens configurations]. Excellent agreement between the experimental results and numerical simulation is observed. Our simulation results demonstrate that the laser induced planar acoustic wave can be focused down to several tens of micron size and several bars in pressure.

Laser induced high frequency acoustic wave generation, propagation, and focusing in water are studied. A large area, flat, and short duration acoustic wave was generated by the thermoelastic interaction of a homogenized short pulsed laser beam with the liquid-solid interface and propagated at the speed of sound. Laser flash Schlieren photography was used to visualize the transient interaction of the flat acoustic wave with a cylindrical concave lens and the subsequent acoustic wave focusing. Numerical simulations showed the acoustic wave could be focused to several tens of microns in size and 7bars in pressure.

Nanowires can potentially be used with low-cost flexible plastic substrates for applications such as large-area displays and sensor arrays. However, high temperature processing steps such as thermal annealing that are incompatible with plastic substrates are still a major hindrance. Laser annealing permits localized energy input without affecting the underlying substrate and can help overcome this problem. In this study, the excimer laser annealing of silicon nanowires is demonstrated to be an efficient means of activating implanted dopants. The optical absorption of the nanowires is discussed and the effect of parameters such as fluence and number of pulses is investigated.

Nanoparticle solutions are considered promising for realizing low cost printable high performance flexible electronics. In this paper, excimer laser annealing (ELA) was employed to induce melting of solution-deposited ZnO nanoparticles and form electrical conductive porous films. The properties of the films were characterized by scanning electron microscopy, high-resolution TEM, Hall-effect, and photoluminescence measurements. Thin film field effect transistors have been fabricated by ELA without the use of conventional vacuum or any high temperature thermal annealing processes. The transistors show n-type accumulation mode behavior with mobility greater than 0.1 cm2/V-s and current on/off ratios of more than 104. Optimization and control of the laser processing parameters minimized thermal impact on the substrate. This technique can be beneficial in the fabrication of metal oxide based electronics on heat sensitive flexible plastic substrates using low-cost, large-area solution processing combined with direct printing techniques.Nanoparticle solutions are considered promising for realizing low cost printable high performance flexible electronics. In this paper, excimer laser annealing (ELA) was employed to induce melting of solution-deposited ZnO nanoparticles and form electrical conductive porous films. The properties of the films were characterized by scanning electron microscopy, high-resolution TEM, Hall-effect, and photoluminescence measurements. Thin film field effect transistors have been fabricated by ELA without the use of conventional vacuum or any high temperature thermal annealing processes. The transistors show n-type accumulation mode behavior with mobility greater than 0.1 cm2/V-s and current on/off ratios of more than 104. Optimization and control of the laser processing parameters minimized thermal impact on the substrate. This technique can be beneficial in the fabrication of metal oxide based electronics on heat sensitive flexible plastic substrates using low-cost, large-area solution processing combined with d...

Biological molecules perform sophisticated functions in living systems with complexity often far exceeding most of man-made devices and objects. Direct integration of biological components with electronic circuits could drastically increase their efficiency, complexity, and capabilities and result in novel sensing and signaling architectures. Yet, one of the obstacles for this vision of a bionanoelectronic circuit is the absence of a versatile interface that facilitates communication between biomolecules and electronic materials. We have been building platforms that integrates membrane proteins with one-dimensional inorganic materials such as carbon nanotubes and silicon nanowires. In our devices, a nanotube of nanowire is covered by a lipid bilayer that serves both as a universal membrane protein matrix and an insulating shield. I will discuss the fabrication and properties of these “shielded” nanowires and of their use in bionanoelectronic devices that incorporate working membrane proteins in an electronic circuit.