Browsing by Author "Liu, S"

Now showing 1 - 5 of 5

A convenient modular approach of functionalizing aromatic polyquinolines for electrooptic devices
(1999-08-01)
Ma, H
;
Jen, AKY
;
Wu, JY
;
Wu, XM
;
Liu, S
A versatile and generally applicable synthetic method for making second-order nonlinear optical (NLO)side-chain aromatic polyquinolines has been developed. This approach emphasizes the ease of incorporating NLO chromophores onto the pendent phenyl moieties of parent polyquinolines at the final stage via a mild Mitsunobu reaction, which provides the synthesis of NLO polyquinolines with a broad variation of polymer backbones and great flexibility in the selection of chromophores. The synthesized NLO side-chain polyquinolines possess high glass transition temperature (T-g > 200 degrees C), good processability, and excellent thermal stability. The promising results of electrooptic (EO) activity (up to 35 pm/V at 830 nm and 22 pm/V at 1300 nm), optical loss (1.5-2.5 dB/cm), and long-term stability of the poling-induced polar order (r(33) values retained > 90% of their original values at 85 degrees C for more than 1000 h) have demonstrated the advantages of this design approach. The excellent combination of these properties in the resulting polymers have also provided a great promise in the development of EO devices.
A direct determination technique for azimuth alignment in photoelastic modulation ellipsometry
(1999-12-01)
Chao, YF
;
Wang, CK
;
Liu, S
;
光電工程學系
;
Department of Photonics
Instead of the nulling method, a three-intensity-measurement technique is proposed to determine the azimuth deviation of the polarizer (P), photoelastic modulator (PEM) and analyzer (A) with respect to the specimen surface for ellipsometric measurements. After the initial alignment in a straight-through setup, we adjusted the azimuth of P at 45 degrees to the strain axis of the PEM. Arranging a Polarizer-PEM-Sample-Analyzer ellipsometer by subjecting a specimen at the required incident angle, we measured a set of three DC radiances at the zero point of the zero-order Bessel function. In addition to the azimuth deviation, the ellipsometric parameter can also be determined from the same measurements.
An assessment of single-electron effects in multiple-gate SOI MOSFETs with 1.6-nm gate oxide near room temperature
(2006-03-01)
Lee, W
;
Su, P
;
Chen, HY
;
Chang, CY
;
Su, KW
This letter provides an assessment of single-electron effects in ultrashort multiple-gate silicon-on-insulator (SOI) MOSFETs with 1.6-nm gate oxide. Coulomb blockade oscillations have been observed at room temperature for gate bias as low as 0.2 V. The charging energy, which is about 17 meV for devices with 30-nm gate length, may be modulated by the gate geometry. The multiple-gate SOI MOSFET, with its main advantage in the suppression of short-channel effects for CMOS scaling, presents a very promising scheme to build room-temperature single-electron transistors with standard silicon nanoelectronics process.
Highly efficient red electrophosphorescent devices based on an iridium complex with trifluoromethyl-substituted pyrimidine ligand
(2004-08-30)
Niu, YH
;
Chen, BQ
;
Liu, S
;
Yip, H
;
Bardecker, J
Highly efficient red-emitting electrophosphorescent devices were fabricated by doping an iridium (Ir) complex containing trifluoromethyl (CF3)-substituted pyrimidine ligand into a conjugated bipolar polyfluorene with triphenylamine and oxadiazole as side chains. The device efficiency can be enhanced through effective exciton confinement using a layer of 1,3,5-tris(N- phenylbenzimidazol-2-yl)benzene on the cathode side and a layer of in situ polymerized tetraphenyldiamine-perfluorocyclobutane on the anode side. For a blend with 5 wt % of the Ir complex, a maximum external quantum efficiency of 7.9 photon/electron % and a maximum brightness of 15800 cd/m(2) are reached with Commission Internationale de L'Eclairage chromaticity coordinates of x=0.65 and y=0.34. (C) 2004 American Institute of Physics.
Inversion MOS capacitance extraction for ultra-thin gate oxide using BSIM4
(2005)
Lee, W
;
Su, KW
;
Chiang, CS
;
Liu, S
;
Su, P