In this paper, we propose a new method for detecting label-free T4-DNA molecules quantitatively using a surface plasmon resonance (SPR) technique on a gold thin film. We used a solution that dissolved T4-DNA molecules in pure water, and examined the relationship between DNA concentration change and SPR angle change in the solution. As a result, it was confirmed that the SPR angle change increased with increasing DNA concentration change. Therefore, it was feasible to detect the DNA concentration change using the SPR technique. Furthermore, to examine and detect a single or a few DNA molecule, we tried to fabricate an SPR chip in which SPR area is narrowed so that it has the same effect as focusing the beam. To narrow the SPR area, we decreased the area of gold thin film in this chip, and, to reflect light from only the area of gold thin film, the area without a gold thin film was micromachined to increase its unevenness for the reduction of light reflection. By the above-mentioned method, we examined the possibility of detecting a label-free DNA molecule using the SPR technique.

An electron transfer mediated amperometric enzyme biosensor based on a plasma-polymerized thin film of dimethylaminomethylferrocene (DMAMFc) is reported. A nanoscale thin polymer film containing a redox mediator was plasma-deposited directly onto an electrode with physisorbed glucose oxidase (GOD). Since the redox sites were introduced in the vicinity of the reaction centers of GOD, a highly efficient electron transfer system was formed in which almost all the reaction centers of GOD were connected to redox sites of the polymer matrix. The advantages of this strategy were: no need for prior or further chemical modification of the enzyme molecules, and simplicity of design compared with the use of a conventional polymer matrix. Moreover, the fact that the film deposition was performed using a microfabrication-compatible organic plasma promised great potential for high-throughput production of bioelectronic devices.

Molecular aligned naphthacene thins films were fabricated using vacuum evaporation and the rubbing method. The attenuated total reflection (ATR) and emission light properties from surface plasmon (SP) excitation due to molecular luminescence were investigated for these films. The long axis of the rod-like molecule was estimated to align perpendicular to the rubbing direction. The ATR and emission light properties depended on the molecular orientation.

A high-speed drive technique is introduced in which addressing is done by eliminating, instead of accumulating, the wall charges. In the proposed scheme, wall charges are accumulated in all the cells in advance, and then the address discharges take place in selected cells to eliminate the wall charges. Sustain discharges are generated in these cells. In order to realize the proposed address scheme, re-designing of a setup waveforms was necessary. The data pulse of 1.33 µs wide and 84 V was realized in a Ne+10%Xe PDP. A contrast of 3,600:1 was obtained by providing one setup period in a TV field.

This letter proposes an efficient method to find the optimum subfield code, which minimizes the visual artifacts on the motion pictures of the plasma display panel (PDP). Existing codes were constructed to reduce dynamic false contour (DFC) only, and they are fixed codes used for every image. In contrast, the proposed method aims to minimize the total artifacts by DFC and halftone noise (HN), and it finds the best code for a given image, dynamically. First, this letter presents the novel models to estimate the effect of DFC and HN for given codewords and a given image. Then, it presents an efficient method that finds the optimum code for a given image using the well-known shortest-path algorithm. Experimental results, using 459 HDTV images, illustrated that the proposed approach improved the average PSNR by 0.713 dB and 7.004 dB in DFC and HN, respectively, when compared with Gravity Centre Code [1].

In AlGaN/GaN high electron mobility transistors (HEMTs), Si3N4 passivation film brings effective improvements in the current collapse phenomenon, however, the suppression of this phenomenon in a high voltage operation can not be achieved in only the Si3N4 deposition process. In order to solve this problem, we have demonstrated an NH3-plasma surface pretreatment in the chamber of plasma enhanced chemical vapor deposition (PE-CVD) just before Si3N4 deposition process. We found that the optimized NH3-plasma pretreatment could improve the current collapse as compared with only the Si3N4 deposition and an excessive pretreatment made it worse adversely in AlGaN/GaN-HEMTs. It was confirmed by Auger electron spectroscopy (AES) analysis that the optimized NH3-plasma pretreatment decreased the carbon contamination such as hydrocarbon on the AlGaN surface and the excessive pretreatment degraded the stoicheiometric composition of AlGaN surface.

We performed numerical analyses on structure sensitive field emission properties of our proposing plasmon resonant photomixer (PRX) in the terahertz range. The photomixer incorporates doubly interdigitated grating strips for gate electrodes and a vertical resonator structure for realizing highly efficient terahertz emission even at room temperature. We investigated the dependence of total field emission properties of PRX's on their material and dimension parameters. Introduction of low-conductive gate electrodes and ac-coupled 2D periodic plasmon gratings with depleted connecting portions are effective for expanding its lower cutoff frequency. The cutoff frequency, which is around 1.0 THz in standard metal-gates configuration, is expanded to less than 500 GHz. The output intensity could also be amplified more than double. On the other hand, a shorter vertical cavity is effective for expanding its upper cutoff frequency, which is expanded close to vertical resonant frequency, while maintaining the lower cutoff frequency. The combination of these design rules can realize much broader bandwidth operation.

We study the coupled spatio-temporal variations of the electron density and the electric field (electron plasma oscillations) in high-electron mobility transistors using the developed device model. The excitation of electron plasma oscillations in the terahertz range of frequencies might lead to the emission of terahertz radiation. In the framework of the model developed, we calculate the resonant plasma frequencies and find the conditions for the plasma oscillations self-excitation (plasma instability) We show that the transit-time effect in the high-electric field region near the drain edge of the channel of high-electron mobility transistors can cause the self-excitation of the plasma oscillations. It is shown that the self-excitation of plasma oscillations is possible when the ratio of the electron velocity in the high field region, ud, and the gate length, Lg, i.e., the inverse transit time are sufficiently large in comparison with the electron collision frequency in the gated channel, ν. The transit-time mechanism of plasma instability under consideration can superimpose on the Dyakonov-Shur mechanism predicted previously strongly affecting the conditions of the instability and, hence, terahertz emission. The instability mechanism under consideration might shed light on the origin of terahertz emission from high electron mobility transistors observed in recent experiments.

Plasma oscillations in nanometer field effect transistors are used for detection and generation of electromagnetic radiation of THz frequency. Following first observations of resonant detection in 150 nm gate length GaAs HEMT, we describe recent observations of room temperature detection in nanometer Si MOSFETs, resonant detection in GaN/AlGaN HEMTs and improvement of room temperature detection in GaAs HEMTs due to the drain current. Experiments on spectrally resolved THz emission are described that involve room and liquid helium temperature emission from nanometer GaInAs and GaN HEMTs.

We analytically investigated the feasibility of multiplier operation in the terahertz range for our original plasmon resonant photomixer. The photomixer features two unique structures (doubly interdigitated gate gratings and a vertical cavity) for higher radiation efficiencies. Its total field emission properties are the result of a combination of plasmon excitation dynamics and electromagnetic field dynamics. The plasmon excitation formulated by the hydrodynamic equations exhibits fundamental and harmonic resonances whose intensities monotonically decrease with the number of harmonics due to the dispersive plasma damping factors. The electromagnetic dynamics, on the other hand, formulated by the Maxwell's equations, reflect material- and structure-dependent device parameters; the grating-bi-coupled plasmonic cavity together with the vertical cavity structures produce nonlinear field emission properties. This results in extraordinary field enhancement at distinct frequencies inconsistent with the plasmon resonances. The frequency-dependent FDTD (finite difference time domain method) Maxwell's simulation revealed that the field emission peak frequency shifted upward apart from the fundamental mode of plasmon resonant frequency and approached to its second harmonic frequency with increasing the electron density in the plasmon cavity. Calculated total field emission spectra indicated that highly dense 2D-plasmon conditions enable frequency-doubler operation in the terahertz range.

Based on fluoride-based plasma treatment of the gate region in AlGaN/GaN HEMTs and post-gate rapid thermal annealing (RTA), enhancement mode (E-mode) AlGaN/GaN HEMTs with low on-resistance and low knee-voltage were fabricated. The fabricated E-mode AlGaN/GaN HEMT with 1 µm-long gate exhibits a threshold voltage of 0.9 V, a knee-voltage of 2.2 V, a maximum drain current density of 310 mA/mm, a peak gm of 148 mS/mm, a current gain cutoff frequency fT of 10.1 GHz and a maximum oscillation frequency fmax of 34.3 GHz. In addition, the fluoride-based plasma treatment was also found to be effective in lowering the gate leakage current, in both forward and reverse bias. Two orders of magnitude reducation in gate leakage current was observed in the fabricated E-mode HEMTs compared to the conventional D-mode HEMTs without fluoride-based plasma treatment.

Experimental investigations on detection of terahertz radiation are presented. We used plasma wave instability phenomenon in nanometer Silicon field effect transistor. A 30 nm gate length transistor was illuminated by THz radiation at room temperature. We observe a maximum signal near to the threshold voltage. This result clearly demonstrates the possibility of plasma wave THz operation of these nanometer scale devices. The response was attributed to a non resonant detection. We also demonstrate the possibility to observe a resonant detection on the same devices.

The authors have proposed a 1 m2 single-layer slotted waveguide array consisting of conducting baffles and quartz glass strips positioned in front of the slot aperture, which is referred to as a vacuum window, for microwave plasma excitation. The effect of the complicated outer vacuum window hinders the realization of uniform distribution. In this paper, a unit-cell of the alternating-phase fed single-layer slotted waveguide array with the vacuum window is analyzed by generalized scattering matrix method (GSM)-method of moments (MoM) hybridization analysis, and the array is designed to realize uniform aperture electromagnetic field distribution, where the plasma and the chamber is neglected. The GSM-MoM analysis gives reliable numerical results while the MoM has numerical errors due to singularities of Green's function for a long cavity. Uniform aperture EM field distribution outside of the vacuum window is observed in near field measurements using a 1/5 scale model antenna, and the validity of the analysis and design is verified.

HfOxNy thin films formed by the electron cyclotron resonance (ECR) Ar/N2 plasma nitridation of HfO2 films were investigated for high-k gate insulator applications. HfOxNy thin films formed by the ECR Ar/N2 plasma nitridation (60 s) of 1.5-nm-thick HfO2 films, which were deposited on chemically oxidized Si(100) substrates, were found to be effective for suppressing interfacial layer growth or crystallization during postdeposition annealing (PDA) in N2 ambient. After 900 PDA of for 5 min in N2 ambient, it was found that HfSiON film with a relatively high dielectric constant was formed on the HfOxNy/Si interface by Si diffusion. An equivalent oxide thickness (EOT) of 2.0 nm and a leakage current density of 1.010-3 A/cm2 (at VFB-1 V) were obtained. The effective mobility of the fabricated p-channel metal-insulator-semiconductor field-effect transistor (MISFET) with the HfOxNy gate insulator was 50 cm2/Vs, and the gate leakage current of the MISFET with the HfOxNy gate insulator was found to be well suppressed compared with the MISFET with the HfO2 gate insulator after 900 PDA because of the nitridation of HfO2.

Collective transverse plasma modes in Bi2Sr2CaCu2O8+x intrinsic Josephson junctions (IJJs) can be excited by the moving fluxon lattices. Progressive transformation of the standing-wave-like fluxon-lattice configuration from a triangular lattice to a rectangular lattice takes place as the dynamic fluxon-lattice modes are in resonance with the collective transverse plasma modes. In this paper, we review the progress in terahertz-frequency-range electromagnetic wave generation from the IJJs using the resonance between moving fluxon lattice and the collective transverse plasma modes.

A new dual-slope ramp (DSR) reset waveform is proposed to improve the dark room contrast ratio in AC-PDPs. The proposed reset waveform has two different voltage slopes during a ramp-up period. The first voltage slope lower than the conventional ramp voltage slope plays a role in producing the priming particles under the low background luminance, which is considered to be a kind of pre-reset discharge. On the other hand, the second voltage slope higher than the conventional ramp voltage slope produces a stable reset discharge due to the presence of the priming particles, but gives rise to a slight increase in the background luminance. Thus, a bias voltage is also applied during a part of the second voltage-slope period to adjust the background luminance and address discharge characteristics. As a result, the proposed dual-slope reset waveform can lower the background luminance without causing the discharge instability, thereby improving the high dark room contrast ratio of an AC-PDP without reducing the address voltage margin.

The radiation properties of oscillating electric dipoles are studied theoretically for three and four layered systems including a single metallic slab based on angular spectrum representation of vector spherical waves. One of the remarkable results obtained is the transmission energy spectrum showing strong dependence on the thickness of a dielectric layer placed between oscillating electric dipole and metallic surface, which explains the experimental results of molecular fluorescence into surface plasmon modes. The theory based on angular spectrum representation and tunneling current provides us with a clear identification of plasmonic excitation transfer, transmission loss associated with plasmon transport in metallic layer, and energy dissipation or quenching of excitation due to surface plasmon excitation at the metallic surface in relation to the characteristic complex wave number of evanescent waves.

We demonstrate a novel fiber device exhibiting magnetic circular dichroism (MCD) and Faraday rotation in sharpened optical fibers coated with Fe. The degree of MCD was 0.68 in a magnetic field of 0.35 T and the Faraday rotation angle was as great as 110 degrees. Such great magneto-optical effect is due to optical near-field interactions in the sub-wavelength region, i.e., in the tip of the near-field fiber probe. These effects can be attributed to the large magnitude of the magneto optical coefficient of Fe.

In AMS/OFDM systems, base station is in control of the modulation level of each subcarrier, and then, adaptive modulated packet is transmitted from the base station to the mobile station. In this case, the mobile station is required the modulation level information (MLI) to demodulate the received packet. The MLI is generally transmitted as a data symbol, therefore, the throughput is degraded. In an OFDM, the channel response at a particular subcarrier frequency is not supposed to be totally different from its neighboring frequencies, and hence, they must have correlation which depends on the coherence bandwidth of the channel Bc. If we could assign the same modulation level for coherently faded subcarrier block, MLI is required only one time for each subcarrier block. Moreover, we can assign the data on the empty space of pilot signals for increasing the total transmission. In this paper, we propose an adaptive subcarrier block modulation with differentially modulated pilot symbol assistance for downlink OFDM using uplink delay spread.

Due to the cost of multicast state management, multicast address allocation, inter-domain multicast routing of traditional IP multicast scheme, ASM leads to a search for other multicast schemes. This paper presents a new solution to the problems mentioned above based on IPv6. The proposed scheme provides an enhanced scheme supporting the strengths of SSM in basic Xcast. This is achieved by adding MLDv2 operations at recipient's side and a new control plane into existing Xcast. The proposed scheme does not only provide the transparency of traditional multicast schemes to sources and recipients, but it also enhances the routing efficiency in networks. Intermediate routers do not have to maintain multicast state, so that it results in a more efficient and scalable mechanism to deliver native multicast datagrams. Also, the seamless integration in Mobile IPv6 can support multicast efficiently for mobile nodes in IPv6 networks by avoiding tunnel avalanches and tunnel convergence. We've attempted to prove this alternative architecture by both simulation and implementation, respectively. Our approach cannot fundamentally perform for many large groups distributed widely as effectively as traditional multicast schemes. However, we believe that the resulting scheme is simple, efficient, robust, transparent, and to the extent possible, scalable in case that recipients are clustered in subnets.