Browsing by Author "Lin, S. H."

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A 45nm dual-port SRAM with write and read capability enhancement at low voltage
(2007)
Wang, D. P.
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Lia, H. J.
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Yamauchi, H.
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Chen, Y. H.
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Lin, Y. L.
This paper presents circuit techniques to improve write and read capability for dual-port SRAM design fabricated in a 45nm low-power process. The write capability is enhanced by negative write biasing without any reduction in the cell current for the other port. The result shows 12% better improvement with just 1.9% area overhead. This technique has been verified successfully on 65nm and 45nm SRAM chip and improved 120mV lower at 95% yield of minimum operation voltage than a conventional one. The read capability is enhanced by cell current boosting and word line voltage lowering schemes. The SNM is also enhanced significantly. The target is to work below 0.8V with the worst process corner variation.
A master equation approach to the dynamics of zero electron kinetic energy (ZEKE) states and ZEKE spectroscopy
(2011-02-14)
Wang, Yi-Hsieh
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Mineo, H.
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Chao, S. D.
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Selzle, H. L.
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Neusser, H. J.
We have theoretically studied important dynamic processes involved in zero electron kinetic energy (ZEKE) spectroscopy using the density matrix method with the inverse Born-Oppenheimer approximation basis sets. In ZEKE spectroscopy, the ZEKE Rydberg states are populated by laser excitation (either a one- or two- photon process), which is followed by autoionizations and l-mixing due to a stray field. The discrimination field is then applied to ionize loosely bound electrons in the ZEKE states. This is followed by using the extraction field to extract electrons from the ZEKE levels which have a strength comparable to that of the extraction field. These extracted electrons are measured for the relative intensities of the ion states under investigation. The spectral positions are determined by the applied laser wavelength and modified by the extraction electric field. In this paper, all of these processes are conducted within the context of the density matrix method. The density matrix method can provide not only the dynamics of system's population and coherence (or phase) but also the rate constants of the processes involved in the ZEKE spectroscopy. Numerical examples are given to demonstrate the theoretical treatments. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3547363]
A Theoretical Investigation of Surface-enhanced Sum-frequency Generation
(2016-01-01)
Yeh, Y. L.
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Lei, J.
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Chen, S. Y.
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Chang, A. H. H.
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Lin, C. K.
Following the surface enhanced Raman scattering (SERS), we shall investigate the possibility of observing surface-enhanced sum-frequency generation (SESFG), which refers to the transformation of ordinary vibrational SFG (i.e. singly resonant) into SESFG. Two mechanisms of SESFG will be studied; one is due to the transformation of singly-resonant vibrational SFG into doubly resonant vibrational SFG (that is, both vibrationally resonant and Raman-scattering resonant) and the other is due to the enhancement of the polarizability in addition to the original vibrational resonance in vibrational SFG.
A Theoretical Investigation of Surface-enhanced Sum-frequency Generation
(2016-01)
Yeh, Y. L.
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Lei, J.
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Chen, S. Y.
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Chang, A. H. H.
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Lin, C. K.
Following the surface enhanced Raman scattering (SERS), we shall investigate the possibility of observing surface-enhanced sum-frequency generation (SESFG), which refers to the transformation of ordinary vibrational SFG (i.e. singly resonant) into SESFG. Two mechanisms of SESFG will be studied; one is due to the transformation of singly-resonant vibrational SFG into doubly resonant vibrational SFG (that is, both vibrationally resonant and Raman-scattering resonant) and the other is due to the enhancement of the polarizability in addition to the original vibrational resonance in vibrational SFG.
Adiabatic treatment for vibrational predissociation of water dimers with channel interactions
(2015-01-01)
Mineo, H.
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Lin, S. H.
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Fujimura, Y.
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應用化學系
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應用化學系分子科學碩博班
The results of calculated vibrational predissociation (VPD) of water dimers are presented. The VPD processes considered here are the followings: initially closed channel of symmetric stretching mode is excited by one quantum, and dissociate to two open channels of the bending mode excitation by one quantum in the donor and acceptor units. The VPD rate constants are calculated in the quantum mechanical approach under the adiabatic approximation. The channel interactions were taken into account in and between the initial and final states. The results obtained by quantum-mechanical approach are compared with both experimental and semi-classical trajectory calculation results.
Adiabatically slow and adiabatically fast driven ratchets
(2012-04-12)
Rozenbaum, V. M.
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Makhnovskii, Yu. A.
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Shapochkina, I. V.
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Sheu, S. -Y.
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Yang, D. -Y.
We revisit two known models of deterministically driven ratchets, which exhibit high energetic efficiency, with the goal to uncover similarities and differences in the principles of their operation. Both the models rely on adiabaticity of the potential change process, however, the adiabaticity that we deal with in the two cases is of different types, slow and fast. It is shown that in the former (latter) case the drift velocity is an even (odd) functional of the potential, with the notable consequence that for the adiabatically slow driven ratchet the necessary symmetry breaking occurs only due to time-dependent parametric perturbations, while the spatial asymmetry of the potential is a mandatory condition for the adiabatically fast driven ratchet to operate. To treat energetic characteristics, the models are restated in terms of traveling potential ratchets. With such an approach, we find that in these cases (i) the conditions of high energetic efficiency to be reached are similar, and (ii) the symmetry properties of the kinetic coefficients are different. Based on our results, a strategy for designing efficient Brownian motors is suggested.
Anharmonic effect of the unimolecular dissociation of CH3COOH
(2014-11-02)
Zhang, Liwei
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Yao, Li
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Li, Qian
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Wang, Guiqiu
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Lin, S. H.
Anharmonic and harmonic rate constants of the reactions have been calculated with the Rice-Ramsperger-Kassel-Marcus theory, and the anharmonic results are higher than the harmonic ones. The anharmonic effect and isotopic effect on the decomposition reactions have also been examined. The anharmonic effect in all the four reactions is obvious, especially at the high temperatures or energies. Relatively, the anharmonic effect on the reaction trans-acetic acid -> TS2 radical is the least obvious among the four reactions. In the microcanonical system, the difference of the rate constants between the deuterated results and the non-deuterated results is not negligible; in other words, the isotopic effect is obvious in all the four reactions. Among these reactions, three of the deuterated results (d, d3 and d4) have a big difference.
Anharmonic effect of the unimolecular dissociation of Glycerol to Glycidol
(2018-09-01)
Li, Qian
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Yao, Li
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Lin, S. H.
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應用化學系
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Department of Applied Chemistry
The unimolecular dissociation rate constants of the dehydration of Glycerol to Glycidol were calculated at the MP2/6-311G(d,p) level using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The anharmonic effect of the reactions was examined by comparing the rate constants at temperatures (700-3000 K) of the canonical case and total energies (25654-53089 cm(-1)) of the microcanonical system. The calculations showed that high temperatures are required for the reaction to proceed. As the temperatures and total energies increased, the rate of reactions increased. However, the growth rate of the unimolecular dissociation rate constants was high and slower both in the canonical and microcanonical systems. Comparative analysis showed that the anharmonic effect was most significant for the reaction C -> TSC -> IV + H2O and least significant for the reaction B -> TSB1 -> I + H2O. The anharmonic effect became more significant as the temperatures and total energies increased. Compared with the microcanonical situation, the anharmonic effect of the canonical system was more pronounced.
Anharmonic Effect of the Unimolecular Dissociation of HFCO and DFCO
(2015-07-01)
Zhong, Jingjun
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Wang, Weiwen
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Li, Qian
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Xia, Wenwen
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Shao, Ying
The unimolecular reactions of HFCO and DFCO have been studied by RRKM theory. The harmonic and anharmonic rate constants of the HFCO and DFCO decompositions have been calculated. The harmonic and anharmonic rate constants increase with the increasing temperatures and total energies both in the canonical and microcanonical systems. The comparison shows that the rate constants of DFCO decomposition are lower than that of the HFCO decomposition. The anharmonic effect and isotope effect have also been investigated. It has been found that the anharmonic effect and isotope effect are not significant either in the canonical or microcanonical system for all the reactions.
Anharmonic Effect of the Unimolecular Isomerization/Decomposition of Benzyne
(2015-04-01)
Li, Qian
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Yao, Li
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Lin, S. H.
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應用化學系
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Department of Applied Chemistry
The anharmonic and harmonic rate constants were calculated for the unimolecular decomposition of o-benzyne, the isomerization of o-benzyne to m-benzyne, the isomerization of m-benzyne to p-benzyne and unimolecular decomposition of p-benzyne by using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory respectively, in the canonical and microcanonical systems. The geometry and the vibrational frequencies were calculated by MP2 and B3LYPmethods with 6-311G(d,p) basis set and the barrier energies were corrected using CBS-QB3 theory. The anharmonic effect on the reactions was also examined. Comparison of results for the decompositions of benzyne indicate that both in microcanonical and canonical cases, the anharmonic effect on the decomposition of the o-C6H4 and p-C6H4 are significant, while the anharmonic effect on the two isomerizations are not pronounced.
Anharmonic effect on unimolecular reactions with application to the photodissociation of ethylene
(2007-07-26)
Yao, L.
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Mebel, A. M.
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Lu, H. F.
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Neusser, H. J.
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Lin, S. H.
The importance of anharmonic effect on dissociation of molecular systems, especially clusters, has been noted. In this paper, we shall present a theoretical approach that can carry out the first principle calculations of anharmonic canonical and microcanonical rate constants of unimolecular reactions within the framework of transition state theory. In the canonical case, it is essential to calculate the partition function of anharmonic oscillators; for convenience, the Morse oscillator potential will be used for demonstration in this paper. In the microcanical case, which involves the calculation of the total number of states for the activated complex and the density of states for the reactant, we make use of the fact that both the total number of states and the density of states can be expressed in the inverse Laplace transformation of the partition functions and that the inverse Laplace transformation can in turn be carried out by using the saddle-point method. We shall also show that using the theoretical approach presented in this paper the total number of states and density of states can be determined from thermodynamic properties and the difference between the method used in this paper and the thermodynamic model used by Krems and Nordholm will be given. To demonstrate the application of our theoretical approach, we chose the photodissociation of ethylene at 157 and 193 nm as an example.
Atomic layer deposition prepared Al-doped ZnO for liquid crystal displays applications
(2018-05-01)
Su, Y. C.
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Chiou, C. C.
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Marinova, V.
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Lin, S. H.
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Bozhinov, N.
Aluminum-doped zinc oxide (AZO) layers are prepared by using atomic layer deposition technique. The obtained layers possess high optical transmittance at visible and near-infrared spectral range. By varying the Al content, optimal growth compositions of AZO are established where the electrical conductivity of the film is highest. Based on performed optical and electrical characteristics measurements, selected AZO films with optimal conductivity are implemented as transparent electrodes in liquid crystal display devices. The electro-optical modulation characteristics of these devices are found to be comparable to those of devices using commercial ITO electrodes.
Autoionization rate constants of zero electron kinetic energy Rydberg states
(2012-03-13)
Mineo, H.
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Wang, Y. H.
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Chao, S. D.
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Lin, S. H.
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應用化學系
We have calculated the vibrational and rotational autoionization rate constants for diatomic molecules H-2, N-2, and HCl in high Rydberg states by employing the density matrix formulation with the inverse Born-Oppenheimer approximation basis set. The purpose is to simulate the main radiationless processes occurring in zero electron kinetic energy (ZEKE) spectroscopy. The quantum numbers and the energy dependences of the calculated autoionization rate constants are represented as the scaling laws via nonlinear regression. These data provide a suitable starting point for quantitative study of the intricate dynamics involved in ZEKE Rydberg states. (C) 2012 Elsevier B. V. All rights reserved.
Blinking suppression of single quantum dots in agarose gel
(2010-01-04)
Ko, H. C.
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Yuan, C. T.
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Lin, S. H.
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Tang, Jau
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應用化學系
Fluorescence blinking is commonly observed in single molecule/particle spectroscopy, but it is an undesirable feature in many applications. We demonstrated that single CdSe/ZnS quantum dots in agarose gel exhibited suppressed blinking behavior. In addition, the long-time exponential bending tail of the power-law blinking statistics was found to be influenced by agarose gel concentration. We suggest that electron transfer from the light state to the dark state might be blocked due to electrostatic surrounding of gel with inherent negatively charged fibers.
Blocked Electron Transfer and Suppressed Blinking of Single CdSe/ZnS Quantum Dots in Agarose Gel
(2010)
Ko, H. C.
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Yuan, C. T.
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Lin, S. H.
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Tang, Jau
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應用化學系
Fluorescence blinking is an interesting phenomenon commonly observed in single molecule/particle spectroscopy and has attracted wide interest recently. Such behavior in quantum dots is undesirable for applications as fluorescence markers. In this report, we observed suppressed blinking for single CdSe/ZnS quantum dots mixed in agarose gel We attributed the suppression to an increase in activation energy so that the charge transfer is blocked from the neutral light state to the charged dark state as the gel concentration increases
Calculation of anharmonic effect on the dissociation of ethylene glycol
(2017-12-01)
Li, Qian
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Yao, Li
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Lin, S. H.
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應用化學系
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Department of Applied Chemistry
The unimolecular dissociation rate constants of ethylene glycol were examined using the MP2/6-311++G(d, p) method based on the Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The effect of anharmonicity on the dissociation rate constants was evaluated at 500-4000 K temperatures of the canonical system and 25,182-50,235 cm(-1) total energies of the microcanonical system. The comparison of the results showed that the H2O elimination reaction played a critical role in the decomposition processes of ethylene glycol. The results of the rate constant calculations indicated that the H2O elimination reaction dominated at low temperatures, whereas the direct C-C bond dissociation reaction (CH2OHCH2OH -> CH2OH+CH2OH) dominated at high temperatures. For channel 1, CH2OH+CH2OH, the anharmonic effect of the canonical system was not observed, while it became more obvious with the increasing total energies in the microcanonical system. For channels 2-5, CH3CHO+H2O, CH2CHOH+H2O, CH3OH+CHOH, and CH2OHCHO+H-2, the anharmonic effect of canonical and microcanonical systems became more obvious with increasing temperatures and total energies. The comparison showed that, for channels 1 and 4, C-C bond dissociation and the anharmonic effect of the microcanonical system were more evident, whereas the anharmonic effect of the canonical system was more predominant for channels 2 (CH3CHO+H2O), 3 (CH2CHOH+H2O), and 5 (CH2OHCHO+H-2).
Calculation of anharmonic effects for the unimolecular dissociation of CH3OOH and its deuterated species CD3OOD using the Rice-Ramsperger-Kassel-Marcus theory
(2015-06-01)
Li, Qian
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Yao, Li
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Lin, S. H.
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應用化學系
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Department of Applied Chemistry
Anharmonic and harmonic rate constants for the unimolecular dissociation of CH3OOH and CD3OOD were calculated using the Rice-Ramsperger-Kassel-Marcus (RRKM) theory at the MP2/6-311++G(3df,3pd) level of theory. The anharmonic effect of the reactions was investigated. Comparison of results for the decompositions of CH3OOH and CD3OOD shows that the direct bond dissociation channel, CH3 (D-3) O + OH (D), is the most dominant reaction. The anharmonic effect plays an important role in the unimolecular dissociation of both CH3OOH and CD3OOD. For channels CH3 (D-3) O + OH (D) and CH3 (D-3) + H (D) O-2, the anharmonic effect of the unimolecular dissociation of CD3OOD is more pronounced than that of the unimolecular dissociation of CH3OOH. For channel H-2 (D-2) CO + H-2 (D-2) O, the anharmonic effect of the unimolecular dissociation of CH3OOH is more pronounced than that of the unimolecular dissociation of CD3OOD. The isotope effect is more distinct in the anharmonic oscillator model.
Calculation of anharmonic effects in the unimolecular dissociation of M2+ (H2O)(2) (M = Be, Mg, and Ca)
(2015-11-17)
Li, Qian
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Yao, Li
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Xia, Wenwen
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Lin, S. H.
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應用化學系
The anharmonic and harmonic rate constants of the unimolecular dissociation of M2+(H2O)(2) (M = Be, Mg, and Ca) were calculated using the Rice-Ramsperger-Kassel-Marcus theory. The anharmonic effects of the reactions were investigated. The results show that the energy barrier of the dissociation of Be2+(H2O)(2) is 68.47 kcal/mol, and the anharmonic (T-4000K = 4.28x10(8) s(-1)) and harmonic (T-4000K = 4.22x10(8) s(-1)) rate constants were close in value in both the canonical and microcanonical systems. The energy barriers of the two steps for the dissociation, Mg2+(H2O)(2) MgOH++H3O+, were 37.41 and 11.39 kcal/mol, and those for the dissociation, Ca2+(H2O)(2) CaOH++H3O+, were 21.15 and 26.42 kcal/mol. The anharmonic effect of the two reactions is significant and cannot be neglected in both the canonical and microcanonical systems. The comparison also shows that the rate constants of the dissociation of Ca2+(H2O)(2) have the maximum values, while those of Be2+(H2O)(2) have the minimum values in the three reactions; however, the anharmonic effect also shows the similar trend in the comparison.
center dot-ray induced effects in Sm-doped strontium borate glasses
(2013)
Marinova, V.
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Tomov, V.
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Chuang, C. I.
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Lin, Y. C.
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Lin, S. H.
Strontium borate glasses SrB4O7 doped with Sm ions are prepared by conventional melting-quenching method. The effect of center dot-ray irradiation on the glass samples is studied by measuring the absorption spectra and the photoluminescence. It is found that the center dot -ray irradiation caused partial reduction of Sm3+ to Sm2+ at room temperature. Borate framework is supposed to be responsible for the Sm3+ to Sm2+ transition.
Characterization of doped Bi4Ge3O12 single crystals by light-induced absorption, electrical and photoelectrical measurements
(2007-02-01)
Petrova, D.
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Marinova, V.
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Liu, R. C.
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Lin, S. H.
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Hsu, K. Y.
Measurement of light-induced absorption changes, dark- and photoconductivity have been performed on Bi4Ge3O12 crystals doped with Fe, Rh and Fe+Rh. All samples exhibited a strong photochromic effect at room temperature, which was fully reversible after thermal annealing. It was found that Rh-doped Bi4Ge3O12 crystals possess a lower dark conductivity (sigma(d) = 5.2 x 10(-14) (Omega.cm)(-1)) at room temperature in comparison with other investigated samples. New centers in the Bi4Ge3O12 inter-band structure, with thermal activation energies between 0.25 and 0.37 eV, have been created by doping with Fe and Rh. Fe-doped and Fe+Rh co-doped samples showed a non-linear photoconductivity dependence on light intensity, under illumination with a 514-nm laser.