Browsing by Author "Wang, XL"

Now showing 1 - 4 of 4

Modeling of quantum effects for ultrathin oxide MOS structures with an effective potential
(2002-12-01)
Li, YM
;
Tang, TW
;
Wang, XL
;
友訊交大聯合研發中心
;
D Link NCTU Joint Res Ctr
In this paper, the effectiveness of the effective potential (EP) method for modeling quantum effects in ultrathin oxide MOS structures is investigated. The inversion-layer charge density and MOS capacitance in one-dimensional MOS structures are simulated with various substrate doping profiles and gate bias voltages. The effective mass is used as an adjusting parameter to compare results of the EP model with that of the Schrodinger-Poisson solution. The variation of this optimum parameter for various doping profiles at different gate voltages is investigated. The overestimated average inverse charge depth by the EP method is quantified and its reason explained. The EP model is a good practical simulation tool for modeling quantum effects but more work needs to be done to improve its accuracy near the interface.
Study of poly(ethylene oxide) electrolyte with polyurethane/sulfonate side chains
(2001-10-17)
Wang, XL
;
Fang, B
;
Wang, L
;
Tang, XZ
;
Chang, FC
Sulfonated dimethyl fumarate (SDMF) was prepared. Poly(ethylene oxide) (PEO) with sodium sulfonate side chains (SPEO) was synthesized by transesterification between SDMF and PEO with molecular weights of 200, 400, 600, 800, and 1000. The SPEO was subsequently mixed as a plasticizer with PEO polyurethane (PU). Samples were characterized by elemental analysis, FTIR, H-1-NMR, gel permeation chromatography, and impedance analysis. The mixture exhibited a homogeneous domain. The maximum conductivity of the CPU1000/SPEO600 was 2.6 x 10(-7) S cm(-1) at room temperature. The relation between the ionic conductivity and the temperature was in agreement with the Arrhenius equation. (C) 2001 John Wiley & Sons, Inc.
Syntheses and characterizations of soft-segment ionic polyurethanes
(1999-04-15)
Wang, XL
;
Li, H
;
Tang, XZ
;
Chang, FC
;
應用化學系
Novel soft-segment ionic polyurethane (linear and crosslinking) have been prepared based up on sodium sulfonate-side chains poly(ethylene oxide) (SPEO). SPEO was synthesized by grafting the sodium sulfonate onto the chain of poly(ethylene oxide) with molecular weights of 400, 600, 800, and 1000. The SPEO and the ionic polyurethane were characterized by elemental analysis, IH;NMR, C-13-NMR, gel permeation chromatography, and impedance analysis. The effect of plasticizer on the ionic conductivity of the polyurethane was also investigated. These solid polymer electrolytes possess a higher ionic conductivity (about 10(-6) S/cm at room temperature) than the corresponding sulfonated hard-segment polyurethane electrolytes. The presence of the hydroxyl group in the electrolyte tends to lower the ionic conductivity. Crosslinking of polyurethane results in the enhancement of the dimensional stability, while maintaining the same level of the ionic conductivity. (C) 1999 John Wiley & Sons, Inc.
Syntheses of poly(ethylene oxide) polyurethane ionomers
(2000-07-05)
Wang, XL
;
Wang, L
;
Li, H
;
Tang, XZ
;
Chang, FC
Sulfonated dimethyl fumarate (SDMF) was prepared with dimethyl fumarate (DNF) and sodium hydrogensulfite (NaHSO3). Sodium sulfonate side-chain poly(ethylene oxide) (SPEO) was synthesized by grafting sodium sulfonate onto the chain of PEO with molecular weights of 400, 600, 800, and 1000. SPEO was used subsequently in step-growth polymerization to give a polyurethane ionomer (SPU). Samples were characterized by element analysis, FTIR, H-1-NMR, EDX mapping, X-ray, gel permeation chromatography, and impedance analysis. The SPUs exhibited an amorphous structure. The maximum conductivity of the SPU was 1.02 x 10(-6) S cm(-1) at the room temperature. (C) 2000 John Wiley & Sons, Inc.