A novel fabrication approach for electrochemical sensing of nicotinamide adenine dinucleotide (NADH) using neutral red (NR) functinalized carbon nanotube/plasma-polymerized film composite electrode is reported. The configuration of sensing electrode was NR-functionalized CNTs sandwiched between two acetonitrile PPFs on sputtered gold thin film. The NR as an electron transfer mediator shuttles the electron from the CNT to gold electrode. Due to the synergistic effect between NR and CNT, the resulting electrode showed the lower detection potential and the larger sensitivity (current) than that of NR or CNT alone. The sensor revealed a sensitivity of 29 µA mM-1 cm-2 at +0.15 V vs. Ag/AgCl, linear dynamic range of 0.08–4.2 mM, a detection limit of 18 µM at S/N=3, and a response time of 7 s.

In this paper, we designed and fabricated large scale micro-light-emitting-diode (LED) arrays and silicon driver for single chip device for realizing as prototypes of heterogeneous optoelectronic integrated circuits (OEICs). The large scale micro-LED arrays were separated by a dry etching method from mesa structure to 16,384 pixels of 128 128, each with a size of 15 µm in radius. Silicon driver was designed the additional bonding pad on each driving transistor for bonding with micro-LED arrays. Fabricated micro-LED arrays and driver were flip-chip bonded using anisotropic conductive adhesive.

We developed a flexible-logic-gate single-electron device (SED) in which logic functions can be selected by changing the voltage applied to the control gate. It consists of an array of nanodots with multiple inputs and multiple outputs. Since the gate electrodes couple capacitively to the many dots underneath, complicated characteristics depending on the combination of the gate voltages yield a selectable logic gate when some of the gate electrodes are used as control gates. One of the important issues is how to design the arrangement of nanodots and gate electrodes. In this study, we fabricated a Si nanodot array with two simple input gates and two output terminals, in which each gate was coupled to half of the nanodot array. Even though the device had a very simple input-gate arrangement and just one control gate, we could create a half-adder function through the use of current maps as functions of the input gate voltages. We found that the nanodots evenly coupled capacitively to both input gates played an important role in getting a basic set of logic functions. Moreover, these results guarantee that a more complicated input-gate structure, in which each gate evenly couples many nanodots, will yield more complicated functions.

We herein investigate the operation stability of the single-electron-pump (SEP) refrigerator with respect to thermal and dimensional fluctuations. The SEP refrigerator was found to successfully demonstrate single-electron extraction and injection at temperatures up to 2 K. Although the dimensional fluctuation in junction capacitance will seriously affect operation, the effect of the gate capacitance fluctuation is unlikely to be severe.

Three types of electron injection scheme: both side injection scheme and self-repair one side injection scheme Type A (injection for once) and Type B (injection for twice) are proposed and analyzed comprehensively for 65 nm technology node 6T- and 8T-SRAM cells to find the optimum injection scheme and cell architecture. It is found that the read speed degrades by as much as 6.3 times in the 6T-SRAM with the local injected electrons. However, the read speed of the 8T-SRAM cell does not degrade because the read port is separated from the write pass gate transistors. Furthermore, the self-repair one side injection scheme is most suitable to solve the conflict of the half select disturb and write characteristics. The worst cell characteristics of Type A and Type B self-repair one side injection schemes were found to be the same. In the self-repair one side injection 8T-SRAM, the disturb margin increases by 141% without write margin or read speed degradation. The proposed schemes have no process or area penalty compared with the standard CMOS-process.

Large-scale adoption of electronic healthcare applications requires semantic interoperability. The new proposals propose an advanced (multi-level) DBMS architecture for repository services for health records of patients. These also require query interfaces at multiple levels and at the level of semi-skilled users. In this regard, a high-level user interface for querying the new form of standardized Electronic Health Records system has been examined in this study. It proposes a step-by-step graphical query interface to allow semi-skilled users to write queries. Its aim is to decrease user effort and communication ambiguities, and increase user friendliness.

In this paper, a sepic-type single-stage electronic ballast (STSSEB) is proposed, which is derived from the combination of a sepic converter and a half-bridge inverter. The ballast can not only step down input voltage directly but achieve high power factor, reduce voltage stress, improve efficiency and lower cost. Since component stress is reduced significantly, the presented ballast can be applied to high voltage mains. Derivation of the STSSEB is first presented. Then, analysis, design and practical consideration for the STSSEB are discussed. A 347 Vac 60 W prototype has been simulated and implemented. Simulations and experimental results have verified the feasibility of the proposed STSSEB.

We investigated optical transmission characteristics of aluminum thin films with periodic hole arrays in sub-wavelength. We divided white light into several color spectra using a color filter based on the surface plasmon resonance (SPR) utilizing aluminum showing high plasma frequency. By optimizing a hole-array period, hole shape, polarization and index difference of two surface, transmittance of 30% and full-width at half-maximum of around 100 nm were achieved.

An electronic ticket is a contract, in digital format, between the user and the service provider, and reduces both economic costs and time in many services such as air travel industries or public transport. However, the security of the electronic ticket has to be strongly guaranteed, as well as the privacy of their users. We present an electronic ticketing system that considers these security requirements and includes the exculpability as a security requirement for these systems, i.e. users and the service provider can not falsely accuse each other of misbehavior. The system ensures that either both parties receive their desired data from other or neither does (fair exchange). Another interesting property is reusability. Thanks to reusability the tickets can be used a predefined number of times with the same security as single tickets. Furthermore, this scheme takes special care of the computational requirements on the users side by using light-weight cryptography. We show that the scheme is usable in practice by means of its implementation using mobile phones with Near Field Communication (NFC) capabilities.

To realize a single or several molecule device, the following are necessary: (1) an electrical wiring method that is not destructive to the molecular aggregates and does not affect the electronic state of the molecules, (2) noncontact and controllable molecular manipulation technology, (3) oriented growth techniques especially to prepare a nanodevice employing an anisotropic molecular system. In this paper, recently developed electric-field assisted growth and its application to molecular device fabrication are presented.

Current density-voltage (J-V) and capacitance-voltage (C-V) characteristics of P3HT/n--silicon heterojunction diodes were investigated to clarify the carrier conduction mechanism at the organic/inorganic heterojunction. The J-V characteristics of the P3HT/n--Si junctions can be explained by a Schottky diode model with an interfacial layer. Diode parameters such as Schottky barrier height and ideality factor were estimated to be 0.78 eV and 3.2, respectively. The C-V analysis suggests that the depletion layer appears in the n--Si layer with a thickness of 1.2 µm from the junction with zero bias and the diffusion potential was estimated at 0.40 eV at the open-circuit condition. The present heterojunction allows a photovoltaic operation with power conversion efficiencies up to 0.38% with a simulated solar light exposure of 100 mW/cm2. The forward bias current was enhanced by coating the Si surface with a SiC layer, where the ideality factor was improved to be the level of 1.451.50.

We propose a novel technique to grow the single-walled carbon nanotubes (SWNTs) with specific chirality at the desired position using free electron laser (FEL) irradiation during growth and surface treatment. As a result, only the semiconducting SWNTs grew at the area between triangle electrodes, where the ozone treatment was done to be hydrophilic when an alcohol chemical vapor deposition (ACCVD) process was carried out with the 800 nm FEL irradiation. Although the number of possible chiral index is 22 in the SWNTs grown without the FEL irradiation, the number is much reduced to be 8 by the FEL.

We have been developing low power cryogenic readout electronics for space borne large format far-infrared image sensors. As the circuit elements, a fully-depleted-silicon-on-insulator (FD-SOI) CMOS process was adopted because they keep good static performance even at 4.2 K where where various anomalous behaviors are seen for other types of CMOS transistors. We have designed and fabricated several test circuits with the FD-SOI CMOS process and confirmed that an operational amplifier successfully works with an open loop gain over 1000 and with a power consumption around 1.3 µW as designed, and the basic digital circuits worked well. These results prove that the FD-SOI CMOS process is a promising candidate of the ideal cryogenic readout electronics for far-infrared astronomical focal plane array sensors.

This paper studies a switched dynamical system based on the boost converter with a solar cell input. The solar cell is modeled by a piecewise linear current-controlled voltage source. A variant of peak-current-controlled switching is used in the boost converter. Applying the mapping procedure, the system dynamics can be analyzed precisely. As a main result, we have found an important example of trade-off between the maximum power point and stability: as a parameter (relates to the clock period) varies, the average power of a periodic orbit can have a peak near a period-doubling bifurcation set and an unstable periodic orbit can have the maximum power point.

Fair exchange is an important tool to achieve “fairness” of electronic commerce. Several previous schemes satisfy universally composable security which provides security preserving property under complex networks like the Internet. In recent years, as the demand for electronic commerce increases, fair exchange for electronic vouchers (e.g., electronic tickets, moneys, etc.) to obtain services or contents is in the spotlight. The definition of fairness for electronic vouchers is different from that for general electronic items (e.g., the sender must not do duplicate use of exchanged electronic vouchers). However, although there are universally composable schemes for electronic items, there is no previous study for electronic vouchers. In this paper, we introduce a universally composable definition of fair voucher exchange, that is, an ideal functionality of fair voucher exchange. Also, we prove the equivalence between our universally composable definition and the conventional definition for electronic vouchers. Thus, our formulation of the ideal functionality is justified. Finally, we propose a new fair voucher exchange scheme from non-blocking atomic commitment as black-box, which satisfies our security definition and is adequate for mobile environments. By instantiating general building blocks with known practical ones, our scheme can be also practical because it is implemented without trusted third party in usual executions.

This paper introduces the ensemble Monte Carlo (EMC) method to study the time behavior of single-electron-based logic gates. The method is then applied to a buffer-inverter gate and the results are examined. An analytical model for time behavior at the low-temperature limit is then introduced and its results are compared with those of the EMC. Finally, a compact model for the delay-error behavior of the buffer gate is introduced.

We propose the collective electron tunneling model in the electron injection process between the Nano Dots (NDs) and the two-dimensional electron gas (2DEG). We report the collective motion of electrons between the 2DEG and the NDs based on the measurement of the Si-ND floating gate structure in the previous studies. However, the origin of this collective motion has not been revealed yet. We evaluate the proposed tunneling model by the model calculation. We reveal that our proposed model reproduces the collective motion of electrons. The insight obtained by our model shows new viewpoints for designing future nano-electronic devices.

We have studied the transport property of the Vertical MOSFET (V-MOSFET) with an impurity from the viewpoint of quantum electron dynamics. In order to obtain the position dependence of impurity for the electron transmission property through the channel of the V-MOSFET, we solve the time-dependent Shrodinger equation in real space mesh technique We reveal that the impurity in the source edge can assist the electron transmission from the source to drain working as a wave splitter. In addition, we also reveal the effect of an impurity in the surface of pillar is limited because of its dimensionality. Furthermore, we obtained that the electron injection from the source to the channel becomes difficult due to the energy difference between the subbands of the source and the channel. These results enable us to obtain the guiding principle to design the V-MOSFET in the 10 nm pillar. The results enable us to obtain the guiding principle to design the V-MOSFET beyond 20 nm design rule.

We investigate the problem of switch port allocation in WDM networks that use the hybrid optical-electronic switching node architecture. The objective is to support given traffic demands while minimizing the number of electronic switch ports used, or equivalently minimizing the number of established lightpaths. We first formulate the problem as a mixed integer linear programming (MILP) problem. However, due to the high computational complexity of exact optimization, we develop a simulated annealing (SA) algorithm to get an approximate solution. Results from the SA algorithm demonstrate that, compared to the optical-electrical-optical (O-E-O) node architecture, a WDM network that employs the hybrid switching node architecture requires many fewer lightpaths. We also develop a lightpath assignment heuristic which requires much less computation time than the SA algorithm while maintaining close objective values. The lightpath assignment heuristic is used to investigate the switch port allocation behaviors. Simulation results show that nodes with high degrees or with small average node distances require large numbers of optical switch ports. Moreover, nodes with large amounts of terminate (originated/destined) traffic require large numbers of electronic switch ports. Since the lightpath assignment heuristic requires small computation time, it can be used in the network design process in which a large number of network scenarios must be considered.

This work presents a novel field emission organic light emitting diode (FEOLED), in which an inorganic phosphor thin film is replaced by an organic EL light-emitting layer in the configuration of a field emission display (FED). The field emission electrons emitted from the carbon nanotubes (CNTs) cathode of the proposed FEOLED intensify the electron density in the multi-layer organic materials of the OLED; thus, resulting a higher luminous efficiency than that of a conventional OLED. Additionally, the luminance of the proposed FEOLED can be further increased from 10,820 cd/m2 to 27,393 cd/m2 by raising the current density of OLED through an external electron source. A balanced quantity of electrons and holes in the OLED, which is achieved by the proposed FEOLED increases the number of excitons and attributes the enhancement of luminous efficiency of the OLED. Under the same operating current density, the proposed FEOLED exhibits a higher luminous efficiency than that of a conventional OLED.