A Surface Tailoring Method of Ultrathin Polymer Gate Dielectrics for Organic Transistors: Improved Device Performance and the Thermal Stability Thereof

Tailoring the surface of the dielectric layer is of critical importance to form a good interface with the following channel layer for organic thin film transistors (OTFTs). Here, a simple surface treatment method is applied onto an ultrathin (<15 nm) organosilicon‐based dielectric layer via the initiated chemical vapor deposition (iCVD) to make it compatible with organic semiconductors without degrading its insulating property. A molecular‐thin oxide capping layer is formed on a 15 nm thick poly(1,3,5‐trimetyl‐1,3,5‐trivinyl cyclotrisiloxane) (pV3D3) by a brief oxygen plasma treatment. The capping layer greatly enhances the thermal stability of the dielectrics, without degrading the original mechanical flexibility and insulating performance of the dielectrics. Moreover, the surface silanol functionalities formed by the plasma treatment can also be utilized for the surface modification with silane compounds. The surface‐modified dielectrics are applied to fabricate low‐voltage operating (<5 V) pentacene‐based OTFTs. The highest field‐effect mobility of the device with the surface‐treated 15 nm thick pV3D3 is 0.59 cm² V^?1 s^?1, which is improved up to two times compared to the TFT with the pristine pV3D3. It is believed that the simple surface treatment method can widely extend the applicability of the highly robust, ultrathin, and flexible pV3D3 gate dielectrics to design the surface of the dielectrics to match well various kinds of organic semiconductors.     

2/spl times/4 optical add-drop module with no difference in propagation length

We developed a micromachined X-type 2/spl times/4 optical add-drop module (OADM) featuring no difference in propagation length. Four pairs of lensed fibers are aligned in "X" position, and four micromirrors are located between the pairs of optical fibers. The OADM was fabricated utilizing a silicon-on-insulator process. Electrostatic comb actuators can be driven up to 90 /spl mu/m to change the light path within 1 ms. The insertion loss and the on-off ratio were less than 3 and 70 dB, respectively. The loss uniformity in every channel was 1.5 dB.     

CDMA Mobile System Testbed and Field Test

This paper briefly explains the configuration of CDMA Mobile System (CMS) test bed. The measured fading and delay results of CDMA signal in Taejon area are shown. In comparison to other cellular systems, there are more parameters in the CDMA systems that affect system performance and capacity. We performed the optimization test of the selected parameters and present the effect of each parameter on the performance. This paper presents the capacity and performance test results of CMS. The capacity test was performed on ETRI site of three sectors in Taejon area. The performance tests include call completion rate, busy hour call attempt, and the delay characteristics of voice.     

Analysis and characterization of traveling-wave electrode in electroabsorption modulator for radio-on-fiber application

Comparing with a lumped electroabsorption modulator (EAM), we show the merits of a long EAM with traveling-wave electrode with high radio-frequency (RF) gain that could be used in high-frequency analog application. By terminating the RF output port with the characteristic impedance of 30 /spl Omega/, the device exhibited a large enhancement of 6 dB above 10 GHz in the electrical-to-optical response and a wide fractional bandwidth as estimated from simulation. In addition, an input impedance matching circuit of stub embedded on the device chip was found to be very effective for improving RF characteristics in the narrow band of frequency.     

A Direction‐Based Vascular Pattern Extraction Algorithm for Hand Vascular Pattern Verification

This paper proposes an improved vascular pattern extraction algorithm for person verification applications. The proposed direction‐based vascular pattern extraction (DBVPE) algorithm is based on the directional information of vascular patterns. It applies two different filters to the input images: row vascular pattern extraction filter (RVPEF) for effective extraction of the abscissa vascular patterns and column vascular pattern extraction filter (CVPEF) for effective extraction of the ordinate vascular patterns. We use the combined output of both filters to obtain the final hand vascular patterns. Unlike the conventional hand vascular pattern extraction algorithm, the directional extraction approach prevents loss of the vascular pattern connectivity. To validate the DBVPE algorithm, we used a prototype system with a DSP processor. The prototype system shows approximately a three‐times better false acceptance rate (FAR) than the conventional single filter algorithm.     

A Windows-based interactive and graphic package for the educationand training of power system analysis and operation

This paper presents a Windows-based interactive graphic package developed by the authors for the education and training of the power system modeling, analysis and operation with a user-friendly graphical user interface (GUI) and visual database management system (VDBMS). To achieve this goal, the package is designed to have following features: a graphic editor to visually edit the power system diagram; Windows-based power system database to interactively manage the data; graphic representations; animation; and interrupting schemes. The application programs in this package include the power flow calculation, transient stability analysis, fault analysis, economic dispatch and automatic load-frequency control. This package may be useful for educational and training purposes     

A blind equalization with the sign algorithm for broadband access

This paper presents an optimal reduced constellation point of sign reduced constellation algorithm (SRCA) for square and nonsquare carrierless amplitude and phase (CAP)/QAM signal constellations. Convergence characteristics of the SRCA algorithm are analyzed and compared to those of the RCA algorithm     

Effects of Al<Superscript>3+</Superscript> substitution on the luminescence properties of LuNbO<Subscript>4</Subscript> doped with Eu<Superscript>3+</Superscript> and Tb<Superscript>3+</Superscript> ions

The effect of Al³⁺ substitution on the enhancement of the luminescence of Lu_1–xAl_xNbO₄:Eu³⁺ and Lu_1–xAl_xNbO₄:Tb³⁺ was investigated. X-ray diffraction patterns confirmed that the Eu³⁺, Tb³⁺, and Al³⁺ ions were fully incorporated into the Lu³⁺ sites. In the case of Lu_1–xAl_xNbO₄:Eu³⁺, the predominant red emission (614 nm) was assigned to the ⁵D₀?→?⁷F₂ transition of Eu³⁺ and for x?=?0–0.05, its intensity increased up to ~125 and 108% under 395 nm (⁷F₀ → ⁵L₆) and a charge transfer band excitation, respectively. For Lu_1–xAl_xNbO₄:Tb³⁺, the strongest emission band peaking at 551 nm was attained in the green region among multiple emission bands corresponding to the ⁵D₄?→?⁷F_J transitions of Tb³⁺. Increasing the x values from 0 to 0.05 increased the green emission significantly by ~137%. These phenomena were explained by the local structural distortions and crystal field asymmetry surrounding Eu³⁺ and Tb³⁺, which were attributed to a large difference in the ionic radii of Al³⁺ and Lu³⁺.