Browsing by Author "Yang, SL"

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Characterization of self-assembled InAs quantum dots with InAlAs/InGaAs strain-reduced layers by photoluminescence spectroscopy
(2005-04-15)
Chang, KP
;
Yang, SL
;
Chuu, DS
;
Hsiao, RS
;
Chen, JF
The optoelectronic characteristics of self-assembled InAs quantum dots (QDs) with strain-reduced layers (SRLs) were investigated using photoluminescence (PL) spectroscopy. Various SRLs that combine In0.14Al0.86As and In0.14Ga0.86As with the same total thickness were examined to ascertain their confining effect on carriers in InAs QDs. The emission wavelength is blueshifted as the thickness of InAlAs is increased. The energy separation between the ground state and the first excited state of QDs with InAlAs SRLs greatly exceeds that of QDs with InGaAs SRLs. Atomic force microscopic images and PL spectra of the QD samples demonstrated that high-quality InAs QDs with long emission wavelengths and a large energy separation can be generated by growing a low-temperature, thin InAlAs SRL onto self-assembled QDs. (C) 2005 American Institute of Physics.
Deep hole traps created by gamma-ray irradiation of GaInP
(2001-12-01)
Sung, WJ
;
Liu, TY
;
Yang, SL
;
Huang, KF
;
Tseng, TY
Deep hole traps, created by gamma-ray irradiation of Al/GaInP Schottky diodes grown by metal-organic chemical vapor deposition (MOCVD) were studied by using deep level transient spectroscopy (DLTS) technique. Two distinct deep hole traps, A and B, were observed in the irradiated GaInP samples, According to the analysis of trap concentration in various samples, the trap A is verified as a bulk defect located at 0.29 eV above the valance band. Meanwhile, the trap B is an interface state originated from the junctions of Al/Mg-doped GaInP contacts.
Gamma-ray induced deep electron traps in GaInP
(2001-09-01)
Sung, WJ
;
Liu, TY
;
Yang, SL
;
Huang, KF
;
Tseng, TY
Deep electron traps created by gamma-ray irradiation of Au/GaInP Schottky diodes grown by metal-organic chemical vapor deposition (MOCVD) were studied by using deep level transient spectroscopy (DLTS) technique. Three distinct deep electron traps, G1, G2 and G3, were observed in the irradiated GaInP samples. According to the analysis of trap properties in various samples. trap G1 is verified as a bulk defect located at 0.13 eV below the conduction band, while trap G2 and G3 are interface states originated from the junctions of Au/Te-doped GaInP contacts.
Identification and characterization of KvgAS, a two-component system in Klebsiella pneumoniae CG43
(2003-01-21)
Lai, YC
;
Lin, GT
;
Yang, SL
;
Chang, HY
;
Peng, HL
A two-component system encoding gene cluster kvgAS that is present only in virulent Klebsiella pneumoniae CG43 was isolated and its sequence determined. RT-PCR and Southern analysis demonstrated that kvgAS is organized as an operon. No apparent effect of a kvgS deletion on bacterial virulence was observed in a mouse peritonitis model. In the presence of paraquat or 2,2-dipyridyl, the activity of kvgAS promoter in the kvgS mutant was found to be reduced to half of the level in the wild-type strain. The data suggest that the KvgAS system is autoregulated and plays a role in countering free radical stresses and sensing iron-limiting conditions. (C) 2002 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.
Identification of genes present specifically in a virulent strain of Klebsiella pneumoniae
(2000-12-01)
Lai, YC
;
Yang, SL
;
Peng, HL
;
Chang, HY
;
生物科技學系
Klebsiella pneumoniae is a common cause of septicemia and urinary tract infections. The PCR-supported genomic subtractive hybridization was employed to identify genes specifically present in a virulent strain of K. pneumoniae. Analysis of 25 subtracted DNA clones has revealed 19 distinct nucleotide sequences. Two of the sequences were found to be the genes encoding the transposase of Tn3926 and a capsule polysaccharide exporting enzyme. Three sequences displayed moderate homology with bvgAS, which encodes a two-component signal transduction system in Bordetella pertussis. The rest of the sequences did not exhibit homology with any known genes. The distribution of these novel sequences varied greatly in K. pneumoniae clinical isolates, reflecting the heterogeneous nature of the K. pneumoniae population.
Polymer hot-carrier transistor
(2005-12-19)
Chao, YC
;
Yang, SL
;
Meng, HF
;
Horng, SF
;
物理研究所
Metal-base hot-carrier transistor with conjugated polymer emitter and collector is demonstrated. The device is fabricated by multiple spin coating with the metal base sandwiched between two polymers. A thin insulating layer of LiF is inserted between the emitter and base to enhance the hot carrier kinetic energy and reduce mutual dissolution. Using poly(9-vinylcarbazole) as the emitter, Al as the base, and poly(3-hexylthiophene) as the collector, common-emitter current gain of 25 is obtained with operation voltage as low as 5 V.
Stretch-wire system for integral magnetic field measurements
(2001-07-21)
Hwang, CS
;
Hong, CH
;
Lin, FY
;
Yang, SL
;
電子物理學系
A stretch-wire system was developed to measure and characterize the first and second magnetic fields integral of insertion devices and the harmonic field components of lattice magnet. This simple wire support structure was built with a reliable high precision, and high-speed automatic measurement system for measuring the transversal field integrals of various kind magnets. The measurement precision of the system is 1.5 G cm (70 G cm(2)) for the first (second) field integral of the insertion devices and 0.01% for the harmonic field components analysis of the lattice magnets. The scanning time for a complete measurement is five minutes for the first and second field integral distribution, and four minutes for the harmonic field components. (C) 2001 Elsevier Science B.V. All rights reserved.
Studies of grain size effects in rf sputtered CdS thin films
(1996-06-15)
Tsai, CT
;
Chuu, DS
;
Chen, GL
;
Yang, SL
;
電子物理學系
CdS thin films with various grain sizes were produced by rf sputtering and in situ postannealing processes. For a series of annealing time intervals, the average grain sizes of an as-deposited thin film with thickness similar to 4000 Angstrom were found to vary from similar to 280 to similar to 1500 Angstrom. Three bands located in the green, yellow, and red regions were observed in photoluminescence (PL) spectra of these as-deposited films. The temperature dependence of (PL) spectra of CdS microcrystals was investigated. The variations of the (PL) spectra with average grain size and thickness of CdS thin films were also studied. It was found that the intensity of the yellow band was increased as increasing the film thickness while the intensity of the red band was decreased as the grain size of the film became larger. The peak positions of the yellow and red bands were found to be blue-shifted as the films became thinner. (C) 1996 American Institute of Physics.
Studies of grain size effects in rf sputtered CdS thin films
(1996-06-15)
Tsai, CT
;
Chuu, DS
;
Chen, GL
;
Yang, SL
;
電子物理學系
CdS thin films with various grain sizes were produced by rf sputtering and in situ postannealing processes. For a series of annealing time intervals, the average grain sizes of an as-deposited thin film with thickness similar to 4000 Angstrom were found to vary from similar to 280 to similar to 1500 Angstrom. Three bands located in the green, yellow, and red regions were observed in photoluminescence (PL) spectra of these as-deposited films. The temperature dependence of (PL) spectra of CdS microcrystals was investigated. The variations of the (PL) spectra with average grain size and thickness of CdS thin films were also studied. It was found that the intensity of the yellow band was increased as increasing the film thickness while the intensity of the red band was decreased as the grain size of the film became larger. The peak positions of the yellow and red bands were found to be blue-shifted as the films became thinner. (C) 1996 American Institute of Physics.