Browsing by Author "Lue, JT"

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Addenda to photoluminescence and electron paramagnetic resonance studies of defect centers in porous silicon
(2002-01-15)
Lue, HT
;
Tseng, CY
;
Lue, JT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
This work includes addenda to the paper entitled photoluminescence and electron paramagnetic resonance studies of defect centers in porous silicon (PS) which was published in this journal. The readers can readily obtain the principal values of g(parallel to) and g(perpendicular to) from the de-convolution of the effective principal g-values of the spin resonance data measured at various rotating angles of the magnetic field and the crystal axes. (C) 2002 Elsevier Science B.V. All rights reserved.
Fermi and anti-Fermi glass transition and subband resonant quantum tunneling in Nb/Ti metallic multilayer films
(2000-04-01)
Lue, JT
;
Liang, SY
;
Lee, YW
;
Lue, HT
;
電子工程學系及電子研究所
Multilayer of Nb/Ti and NbN/Ti films with 30 periodic structure were sputtered onto silicon substrates. The current-voltage characteristics measured along the vertical junction at low temperatures exhibit nonlinear step-wise curves. The resonant subband quantum tunneling in the metallic multiple quantum wells can satisfactorily express these peculiar behaviors. The Fermi and anti-Fermi glass transition showing itinerant metallic and insulating conduction properties are also observed at low currents and near critical temperatures.
Microwave penetration depth measurement for high T-c superconductors by dielectric resonators
(2002-06-01)
Lue, HT
;
Lue, JT
;
Tseng, TY
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
The penetration depth A(T) dependence on temperatures for high T. superconducting YBa2Cu3O7-delta thin films stored in various environments was measured by a well-designed microwave dielectric resonator. A d-wave T-2 dependence was observed at low temperatures, while an exponential dependence of the penetration depth lambda(T) relevant to the s wave was detected as temperature increases due to thermal fluctuation. An abnormal upturn of the penetration depth at temperatures below 10 K attributed to the surface current carried by the defect surface-induced Andreev bound states can be apparently observed without applying heavy-ion bombardment from this relatively higher frequency measurement. Readers who endeavor to start this kind of measurement can use the well-modified dielectric cavity in conjunction with the detailed measuring procedure.
Photoluminescence and electron paramagnetic resonance studies of defect centers in porous silicon
(2000-06-15)
Lue, HT
;
Huang, BY
;
Lue, JT
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
Photoluminescence (PL) and electron spin resonance (ESR) spectrometers were exploited to study the Pb defect centers in porous silicon (PS) under various heat treatments. The breaking of Si-H-x and Si-O-H bonds in PS by thermal annealing changes the emission wavelength and increases the recombination centers resulting in degrading the PL intensity. Four kinds of dangling bonds on interfaces of silicon (1 1 1), (1,-1,-1), (-1,1,-1), and (-1,-1,1) faces and SiO2 with C-3V symmetry were identified. The skeleton structure of PS collapsed under thermal annealing. Annealing in hydrogen gas, which is controvertible to the pervasive anticipation, cannot passivate the dangling bonds introduced at high temperatures. (C) 2000 Elsevier Science S.A. All rights reserved.