Low-temperature bonding methods of optoelectronic chips, such as laser diodes (LD) and photodiode (PD) chips, have been the focus of much interest to develop highly functional and compact optoelectronic devices, such as microsensors and communication modules. In this paper, room-temperature bonding of the optoelectronic chips with Au thin film to coined Au stud bumps with smooth surfaces (Ra: 1.3nm) using argon and hydrogen gas mixture atmospheric-pressure plasma was demonstrated in ambient air. The die-shear strength was high enough to exceed the strength requirement of MIL-STD-883F, method 2019 (×2). The measured results of the light-current-voltage characteristics of the LD chips and the dark current-voltage characteristics of the PD chips indicated no degradation after bonding.

Gallium oxide is expected as a channel material for thin film transistors. In the conventional technologies, gallium oxide has been tried to be fabricated by atomic layer deposition (ALD) at high temperatures from 100--450$^{circ}$C, although the room-temperature (RT) growth has not been developed. In this work, we developed the RT ALD of gallium oxide by using a remote plasma technique. We studied trimethylgallium (TMG) adsorption and its oxidization on gallium oxide surfaces at RT by infrared absorption spectroscopy (IRAS). Based on the adsorption and oxidization characteristics, we designed the room temperature ALD of Ga$_{2}$O$_{3}$. The IRAS indicated that TMG adsorbs on the gallium oxide surface by consuming the adsorption sites of surface hydroxyl groups even at RT and the remote plasma-excited water and oxygen vapor is effective in oxidizing the TMG adsorbed surface and regeneration of the adsorption sites for TMG. We successfully prepared Ga$_{2}$O$_{3}$ films on Si substrates at RT with a growth per cycle of 0.055,nm/cycle.

Nitrogen adsorption on thermally cleaned Si(100) surfaces by pure and plasma excited NH$_{3}$ is investigated by extit{in situ} IR absorption spectroscopy and ex-situ X-ray photoelectron spectroscopy with various temperatures from RT (25$^{circ}$C) to 800$^{circ}$C and with a treatment time of 5,min. The nitrogen coverage after the treatment varies according to the treatment temperature for both pure and plasma excited NH$_{3}$. In case of the pure NH$_{3}$, the nitrogen coverage is saturated as low as 0.13--0.25 mono layer (ML) while the growth of the nitride film commenced at 550$^{circ}$C. For the plasma excited NH$_{3}$, the saturation coverage was measured at 0.54,ML at RT and it remained unincreased from RT to 550$^{circ}$C. This indicates that the plasma excited NH$_{3}$ enhances the nitrogen adsorption near at RT. It is found that main species of N is Si$_{2}=$ NH in case of the plasma excited NH$_{3}$ at RT while the pure NH$_{3}$ treatment gives rise to the Si--NH$_{2}$ passivation with Si--H at RT. We discuss the mechanism of the nitrogen adsorption on Si(100) surfaces with the plasma excited NH$_{3}$ in comparison with the study on the pure NH$_{3}$ treatment.

A quartz-crystal-microbalance (QCM) and surface-plasmon-resonance (SPR) hybrid sensor was prepared, and the depositions of polymer electrolytes layer-by-layer (LbL) films were observed in situ. The estimated thicknesses obtained from the QCM method were different from those obtained from the SPR method. This was estimated to be caused by film swelling and water contained in the film.

The fabrication of a grating structure formed by a solid-state electrolyte layer on a dye-TiO$_{2}$ film by the nanoimprinting technique using a polydimethylsiloxane (PDMS) stamp and its application in photoelectric conversion devices are described. The PDMS grating pattern is imprinted from blu-ray disc recordable. A silver electrode was deposited on the patterned solid-state electrolyte layers. Surface plasmon resonance (SPR) excitation was observed in the fabricated solar cells by irradiation with white light. The photoelectric conversion properties were measured to study the effect of the two types of SPR excitations, i.e., the propagating surface plasmon on the Ag grating surface and the localized surface plasmon from the Au nanoparticles on TiO$_{2}$.

For break arcs occurring between Ag and Ag/SnO$_2$ 12,wt% electrical contact pairs, the electrical conductivity, viscosity and specific heat at constant pressure are calculated as thermodynamic and transport properties. Mixture rates of contact material vapor are 0%, 1%, 10% and 100%. Influence of the contact material on the properties is investigated. Temperature for the calculation ranges from 2000,K to 20000,K. Following results are shown. When the mixture rate is changed, the electrical conductivity varies at lower temperature (< 10000,K), and the viscosity and specific heat vary widely at all temperature range. The electrical conductivity is independent of the mixture rate when the temperature is exceeding 10000,K. The thermodynamic and transport properties are independent of the kind of the contact materials.

This paper proposes a new address method to reduce the address power consumption in an AC plasma panel display (AC-PDP). We apply an overlap scan method, in which the scan pulse overlaps with those of the previous scan time and the next scan time. The overlap scan method decreases the address voltage and consequently reduces the address power consumption. However, the drawback of this method is the narrow address voltage margin. This occurs because the maximum address voltage decreases much more than the minimum address voltage does. In order to increase the address voltage margin, we apply a two-step address voltage waveform, in the overlap scan method. In this case, the maximum address voltage increases; however, the minimum address voltage is almost the same. This leads to a wide address voltage margin. Moreover, the two-step address voltage waveform reduces the address power consumption, because the address voltage rises and falls in two steps using an energy recovery capacitor. Consequently, the experimental results show that the new address method reduces the address power consumption by 19.6,Wh (58%) when compared with the conventional method.

The main purpose of this paper is to apply the boundary integral equation (BIE) method to the analysis of spoof localized surface plasmons (spoof LSPs) excited in a perfectly conducting cylinder with longitudinal corrugations. Frequency domain BIE schemes based on electric field integral equation (EFIE), magnetic field integral equation (MFIE) and combined field integral equation (CFIE) formulations are used to solve two-dimensional electromagnetic (EM) problems of scattering from the cylinder illuminated by a transverse electric plane wave. In this approach effects of spoof LSPs are included in the secondary surface current and charge densities resulting from the interaction between the plane wave and the cylinder. Numerical results obtained with the BIE schemes are validated by comparison with that of a recently proposed modal solution based on the metamaterial approximation.

The body-of-revolution finite-difference time-domain method (BOR-FDTD) based on the locally one-dimensional (LOD) scheme is extended to a frequency-dependent version for the analysis of the Drude and Drude-Lorentz models. The formulation is simplified with a fundamental scheme, in which the number of arithmetic operations is reduced by 40% in the right-hand sides of the resultant equations. Efficiency improvement of the LOD-BOR-FDTD is discussed through the analysis of a plasmonic rod waveguide and a plasmonic grating.

To improve metal oxide semiconductor field effect transistors (MOSFET) performance, flat interface between gate insulator and silicon (Si) should be realized. In this paper, the influence of Si surface roughness on electrical characteristics of MOSFET with hafnium oxynitride (HfON) gate insulator formed by electron cyclotron resonance (ECR) plasma sputtering was investigated for the first time. The surface roughness of Si substrate was reduced by Ar/4.9%H2 annealing utilizing conventional rapid thermal annealing (RTA) system. The obtained root-mean-square (RMS) roughness was 0.07nm (without annealed: 0.18nm). The HfON was formed by 2nm-thick HfN deposition followed by the Ar/O2 plasma oxidation. The electrical properties of HfON gate insulator were improved by reducing Si surface roughness. It was found that the current drivability of fabricated nMOSFETs was remarkably increased by reducing Si surface roughness. Furthermore, the reduction of Si surface roughness also leads to decrease of the 1/f noise.

A novel fabrication approach for the amperometric biosensor composed of carbon nanotubes (CNT), a plasma-polymerized film (PPF), hexamineruthenium(III)chloride (RU), and enzyme glucose oxidase (GOD) is reported. The configuration of the electrochemical electrode is multilayer films which contain sputtered gold, lower acetonitrile PPF, CNT, RU, GOD, and upper acetonitrile PPF, sequentially. First, PPF deposited on Au acts as a permselective membrane and as a scaffold for CNT layer formation. Second, PPF directly deposited on GOD acts as a matrix for enzyme immobilization. To facilitate the electrochemical communication between the CNT layer and GOD, CNT was treated with nitrogen plasma. The electron transfer mediator RU play a role as the mediator, in which the electron caused by enzymatic reaction transports to the electrode. The synergy between the electron transfer mediator and CNT provides benefits in terms of lowering the operational potential and enhancing the sensitivity (current). The optimized glucose biosensor revealed a sensitivity of 3.4µA mM-1 cm-2 at +0.4V vs. Ag/AgCl, linear dynamic range of 2.5-19mM, and a response time of 6s.

Nowadays, error control codes have become an essential technique to improve the reliability of various digital systems. A new type error control codes called m-spotty byte error control codes are applied to computer memory systems. These codes are essential to make the memory systems reliable. Here, we introduce the m-spotty Rosenbloom-Tsfasman weights and m-spotty Rosenbloom-Tsfasman weight enumerator of linear codes over Fq[u]/(uk) with uk=0. We also derive a MacWilliams type identity for m-spotty Rosenbloom-Tsfasman weight enumerator.

In this paper, we present the validity and potential capacity of a modeling and simulation environment for the nonresonant plasmonic terahertz (THz) detector based on the silicon (Si) field-effect transistor (FET) with a technology computer-aided design (TCAD) platform. The nonresonant and “overdamped” plasma-wave behaviors have been modeled by introducing a quasi-plasma electron charge box as a two-dimensional electron gas (2DEG) in the channel region only around the source side of Si FETs. Based on the coupled nonresonant plasma-wave physics and continuity equation on the TCAD platform, the alternate-current (AC) signal as an incoming THz wave radiation successfully induced a direct-current (DC) drain-to-source output voltage as a detection signal in a sub-THz frequency regime under the asymmetric boundary conditions with a external capacitance between the gate and drain. The average propagation length and density of a quasi-plasma have been confirmed as around 100 nm and 11019/cm3, respectively, through the transient simulation of Si FETs with the modulated 2DEG at 0.7 THz. We investigated the incoming radiation frequency dependencies on the characteristics of the plasmonic THz detector operating in sub-THz nonresonant regime by using the quasi-plasma modeling on TCAD platform. The simulated dependences of the photoresponse with quasi-plasma 2DEG modeling on the structural parameters such as gate length and dielectric thickness confirmed the operation principle of the nonresonant plasmonic THz detector in the Si FET structure. The proposed methodologies provide the physical design platform for developing novel plasmonic THz detectors operating in the nonresonant detection mode.

To improve metal oxide semiconductor field effect transistors (MOSFET) performance, flat interface between gate insulator and silicon should be realized. In this paper, flattening process of Si surface below 1000 utilizing Ar/4.9%H2 annealing and its effect on ultrathin HfON gate insulator formation were investigated. The Si(100) substrates were annealed using conventional rapid thermal annealing (RTA) system in Ar or Ar/4.9%H2 ambient for 1 h. The surface roughness of Ar/4.9%H2-annealed Si was small compared to that of Ar-annealed Si because the surface oxidation was suppressed. The obtained root mean square (RMS) roughness was 0.08 nm (as-cleaned: 0.20 nm) in case of Ar/4.9%H2-annealed at 1000 measured by tapping mode atomic force microscopy (AFM). The HfON surface was also able to be flattened by reduction of Si surface roughness. The electrical properties of HfON gate insulator were improved by the reduction of Si surface roughness. We obtained equivalent oxide thickness (EOT) of 0.79 nm (as-cleaned: 1.04 nm) and leakage current density of 3.510-3 A/cm2 (as-cleaned: 6.110 -1 A/cm2) by reducing the Si surface roughness.

We report enhanced photocurrent properties of dye/Au-loaded titanium dioxide (TiO2) films on Au gratings. Au-loaded TiO2 nanopowders were first synthesized by a modified sol-gel method and then prepared by the impregnation method. We also fabricated dye-sensitized solar cells, which were composed of Au grating/Au-TiO2/TMPyP-SCC LbL (20 bilayers)/electrolyte/ITO substrates. Short-circuit photo-current measurements showed that Au-loaded TiO2 with grating-coupled surface plasmon excitation can enhance the short-circuit photocurrentof the fabricated cells.

The copper nitride surface characteristics according to atmospheric pressure plasma (APP) and excimer ultraviolet (EUV) treatment were compared using XPS and AFM. As the result of XPS analysis result, in C1s, the organic material removal effect was greater for EUV treatment than for APP, and the oxygen content was found to be low. In Cu (933 eV) area, the shoulder peak of Cu compound was detected, and the reduction was greater for EUV processing than for APP. In the AFM phase image which could be analyzed using the superficial viscoelasticity, the same trend was observed. On the copper nitride surface, the weak boundary O layer is formed according to the clean processing, and such phenomenon was interpreted as a factor for lowering the affinity with polymer.

When the Akebono (EXOS-D) satellite passed through the plasmasphere, a series of lightning whistlers was observed by its analog wideband receiver (WBA). Recently, we developed an intelligent algorithm to detect lightning whistlers from WBA data. In this study, we analyzed two typical events representing the clear dispersion characteristics of lightning whistlers along the trajectory of Akebono. The event on March 20, 1991 was observed at latitudes ranging from 47.83 (47,83N) to -11.09 (11.09S) and altitudes between ∼2232 and ∼7537 km. The other event on July 12, 1989 was observed at latitudes from 34.94 (34.94N) and -41.89 (41.89S) and altitudes ∼1420–∼7911 km. These events show systematic trends; hence, we can easily determine whether the wave packets of lightning whistlers originated from lightning strikes in the northern or the southern hemispheres. Finally, we approximated the path lengths of these lightning whistlers from the source to the observation points along the Akebono trajectory. In the calculations, we assumed the dipole model as a geomagnetic field and two types of simple electron density profiles in which the electron density is inversely proportional to the cube of the geocentric distance. By scrutinizing the dipole model we propose some models of dispersion characteristic that proportional to the electron density. It was demonstrated that the dispersion D theoretically agrees with observed dispersion trend. While our current estimation is simple, it shows that the difference between our estimation and observation data is mainly due to the electron density profile. Furthermore, the dispersion analysis of lightning whistlers is a useful technique for reconstructing the electron density profile in the Earth's plasmasphere.

We present the theory and experiment of metal-cavity nanolasers and nanoLEDs flip-chip bonded to silicon under electrical injection at room temperature. We first review the recent progress on micro- and nanolasers. We then present the design rule and our theoretical model. We show the experimental results of our metal-cavity surface-emitting microlasers and compare with our theoretical results showing an excellent agreement. We found the important contributions of the nonradiative recombination currents including Auger recombination, surface recombination, and leakage currents. Finally, experimental demonstration of electrical injection nanoLEDs toward subwavelength nanoscale lasers is reported.

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.

A Drude-critical points (D-CP) model for considering metal dispersion is newly incorporated into the frequency-dependent FDTD method using the simple trapezoidal recursive convolution (TRC) technique. Numerical accuracy is investigated through the analysis of pulse propagation in a metal (aluminum) cladding waveguide. The TRC technique with a single convolution integral is found to provide higher accuracy, when compared with the recursive convolution counterpart. The methodology is also extended to the unconditionally stable FDTD based on the locally one-dimensional scheme for efficient frequency-dependent calculations.