| 1. |
- Carmody, C., et al.
(författare)
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Ion-implanted In0.53Ga0.47As for ultrafast optoelectronic applications
- 2003
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 82:22, s. 3913-3915
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Tidskriftsartikel (refereegranskat)abstract
- Undoped In0.53Ga0.47As epilayers were implanted with 2- MeV Fe+ ions at doses of 1x10(15) and 1x10(16) cm(-2) at room temperature and annealed at temperatures between 500 and 800 degreesC. Hall-effect measurements show that after annealing, layers with resistivities on the order of 10(5) Omega/square can be achieved. Carrier lifetimes as short as 300 fs are observed for samples annealed at 500 and 600 degreesC. For higher annealing temperatures, characteristic times of the optical response are on the order of a few picoseconds.
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| 2. |
- Carmody, C., et al.
(författare)
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Structural, electrical, and optical analysis of ion implanted semi-insulating InP
- 2004
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 95:2, s. 477-482
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Tidskriftsartikel (refereegranskat)abstract
- Semi-insulating InP was implanted with MeV P, As, Ga, and In ions, and the resulting evolution of structural properties with increased annealing temperature was analyzed using double crystal x-ray diffractometry and cross sectional transmission electron microscopy. The types of damage identified are correlated with scanning spreading resistance and scanning capacitance measurements, as well as with previously measured Hall effect and time resolved photoluminescence results. We have identified multiple layers of conductivity in the samples which occur due to the nonuniform damage profile of a single implant. Our structural studies have shown that the amount and type of damage caused by implantation does not scale with implant ion atomic mass.
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| 3. |
- Carmody, C., et al.
(författare)
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Ultrafast carrier trapping and recombination in highly resistive ion implanted InP
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 94:2, s. 1074-1078
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Tidskriftsartikel (refereegranskat)abstract
- MeV P+ implanted and annealed p-InP, and Fe+ implanted and annealed semi-insulating InP have both been shown to produce the high resistivity, good mobility, and ultrafast optical response desired for ultrafast photodetectors. Hall effect measurements and time resolved photoluminescence were used to analyze the electrical and optical features of such implanted materials. Low temperature annealing was found to yield the fastest response times-130 fs for Fe+ implanted and 400 fs for P+ implanted InP, as well as resistivities of the order similar to10(6) Omega/square. It was found that the electrical activation of Fe-related centers, useful for achieving high resistivities in Fe+ implanted semi-insulating InP, was not fully realized at the annealing temperatures chosen to produce the fastest optical response. Implanting p-InP in the dose regime where type conversion occurs, and subsequent annealing at 500degreesC, produces high resistivities and ultrafast carrier trapping times that are only marginally dose dependent.
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| 4. |
- Li, Z-F, et al.
(författare)
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Determination of carrier-transfer length from side-wall quantum well to quantum wire by micro-photoluminescence scanning
- 2003
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Ingår i: Journal of Electronic Materials. - : Springer Science Business Media. - 0361-5235 .- 1543-186X. ; 32:8, s. 913-916
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Tidskriftsartikel (refereegranskat)abstract
- Micro-photoluminescence (mu-PL) line scanning across a single V-groove, GaAs/AlGaAs quantum wire (QWR) has been performed at room temperature, revealing a clear spatial-dependence of the PL. After fitting each PL spectrum by multi-Gaussian line shapes, intensity profiles of each PL component from confined structures have been obtained as functions of the scanning position. The PL quenching of a side-wall quantum well (SQWL) has been recognized in a certain area in the vicinity of the QWR and is interpreted by carrier transfer into the QWR within effective transfer length. By simulating the carrier-transfer process from SQWL to QWR as a convolution of a step function for carrier distribution and a Gaussian function for exciting laser irradiance, the effective transfer length of about 1.8+/-0.3 mum has, therefore, been concluded.
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| 5. |
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| 6. |
- He, X., et al.
(författare)
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Purification of puerarin by beta-cyclodextrin coupled Superose 12 pg
- 2003
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Ingår i: Chin. J. Chromatogr.. ; 21, s. 610-
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Tidskriftsartikel (refereegranskat)abstract
- Puerarin is a kind of Chinese traditional medicine, which has the good medical function to hypertension and angina. In this study puerarin was purified by low-pressure liquid chromatography. The experimental conditions, such as mobile phase, the stationar
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| 7. |
- He,, X., et al.
(författare)
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Purification of the isoflavonoid puerarin by adsorption chromatography on cross-linked 12% agarose
- 2004
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Ingår i: J. Chromatogr. A. ; 1057:1-2, s. 95-100
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Tidskriftsartikel (refereegranskat)abstract
- The isoflavonoid puerarin in extracts of the well-known traditional Chinese drug Radix puerariae (root of the plant Pueraria lobata) can be separated from other isoflavonoids by adsorption chromatography on the cross-linked 12% agarose gel Superose 12 equilibrated in distilled water. The adsorption is totally quenched by the addition of 50% acetic acid. The separation of the isoflavonoids is tentatively ascribed to interaction with the residues of the cross-linking reagents used in the manufacturing process of Superose 12. Thus, no useful separation can be achieved with non-cross-linked 12% agarose gel media. Symmetric elution profiles at high sample loadings (16 mg on a 24 ml column) suggest linear adsorption isotherms for the isoflavonoids.
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| 8. |
- He, X., et al.
(författare)
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Separation and purification of puerarin using beta-cyclodextrin-coupled agarose gel media
- 2004
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Ingår i: J. Chromatogr. A. ; 1022:1-2, s. 77-82
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Tidskriftsartikel (refereegranskat)abstract
- The isoflavonoid puerarin, a well-known traditional Chinese drug, has been purified in one step from an extract of Radix puerariae (root of the plant Pueraria lobata) by adsorption chromatography on an epichlorohydrin polymerized beta-cyclodextrin ligand coupled to brominated allyl-group substituted Sepharose HP. Acetic acid (10%) was used as the mobile phase and the optimum loading capacity was around 1.2 mg crude extract/ml packed gel. The purity of the collected puerarin was about 98% with a recovery of about 62%.
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| 9. |
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| 10. |
- Marcinkevicius, Saulius, et al.
(författare)
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Influence of annealing on carrier dynamics in As ion-implanted epitaxially lifted-off GaAs layers
- 2000
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 76:10, s. 1306-1308
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Tidskriftsartikel (refereegranskat)abstract
- Electrical and dynamical optical characterization of As-ion implanted and annealed GaAs has been performed. Changes of physical properties induced by annealing have been studied in detail by using layers annealed in small steps in the temperature range 500-700 degrees C. The carrier trapping rate increases exponentially with increase of inverse annealing temperature indicating that in ion-implanted GaAs ultrafast carrier capture occurs to the same trapping centers as in low-temperature-grown GaAs. Relatively large resistivity and electron mobility in As-implanted GaAs have been observed after annealing, which shows that this material possesses properties required for a variety of ultrafast optoelectronic applications.
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