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| 2. |
- 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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| 3. |
- 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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| 4. |
- 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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| 5. |
- Jaarsma, Tiny, et al.
(författare)
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Self-care and quality of life in patients with advanced heart failure : the effect of a supportive educational intervention
- 2000
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Ingår i: Heart & Lung. - : Elsevier BV. - 0147-9563 .- 1527-3288. ; 29:5, s. 319-330
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The goal of this study was to determine the effects of a supportive educational nursing intervention on self-care abilities, self-care behavior, and quality of life of patients with advanced heart failure. DESIGN: The study design was an experimental, random assignment. SETTING: The study was located at the University Hospital in Maastricht, The Netherlands. PATIENTS: The study included 179 patients (mean age 73 years, 58% men, New York Heart Association classification III and IV) admitted to a university hospital with symptoms of heart failure. OUTCOME MEASURES: Outcome measures included self-care abilities (Appraisal of Self-care Agency Scale), self-care behavior (Heart Failure Self-care Behavior Scale), 3 dimensions of quality of life (functional capabilities, symptoms, and psychosocial adjustment to illness), and overall well-being (Cantril's ladder of life). INTERVENTION: The intervention patients received systematic education and support by a nurse in the hospital and at home. Control patients received routine care. RESULTS: Self-care abilities did not change as a result of the intervention, but the self-care behavior in the intervention group was higher than the self-care behavior in the control group during follow-up. The effect of the supportive educational intervention on quality of life was limited. The 3 dimensions of quality of life improved after hospitalization in both groups, with no differences between intervention and control group as measured at each follow-up measurement. However, there was a trend indicating differences between the 2 groups in decrease in symptom frequency and symptom distress during the 9 months of follow-up. CONCLUSION: A supportive educational nursing intervention is effective in improving self-care behavior in patients with advanced (New York Heart Association class III-IV) heart failure; however, a more intensive intervention is needed to show effectiveness in improving quality of life.
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| 6. |
- 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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| 7. |
- 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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| 8. |
- Marcinkevicius, Saulius, et al.
(författare)
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Ultrafast carrier dynamics in highly resistive InP and InGaAs produced by ion implantation
- 2004
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Ingår i: ULTRAFAST PHENOMENA IN SEMICONDUCTORS AND NANOSTRUCTURE MATERIALS VIII. - BELLINGHAM : SPIE-INT SOC OPTICAL ENGINEERING. - 0819452602 ; , s. 299-309
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Konferensbidrag (refereegranskat)abstract
- Heavy ion implantation into InP and In0.53Ga0.47As and rapid thermal annealing has been applied to produce materials with high resistivity, good mobility and ultrashort carrier lifetime, as required for ultrafast optoelectronic applications. Two implantation methods have been analyzed: Fe+ implantation into semi-insulating InP and InGaAs, and P+ implantation into p-doped InP and InGaAs. Both approaches allow production of layers with high sheet resistance, up to 10(6) Omega/square for the P+-implanted compounds. Electron mobility in the high resistivity layers is of the order of 10(2) cm(2)V(-1)s(-1). Carrier lifetimes, measured by the time-resolved photoluminescence and reflectivity, can be tuned from similar to100 femtoseconds to tens of picoseconds by choosing implantation and annealing conditions. Measurements of carrier dynamics have shown that carrier traps act as efficient recombination centers, at least for the case of InP. The dependencies of electrical and ultrafast optical properties on the implantation dose and annealing temperature are determined by the interplay between shallow P and As antisite-related donors, deep Fe-related acceptors and defect complexes.
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| 9. |
- Matas, J., et al.
(författare)
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Comparison of face verification results on the XM2VTS database
- 2000
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Ingår i: Proceedings of the 15th International Conference on Pattern Recognition (ICPR'00) - Volume 4. - 0769507506 ; , s. 858-863
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The paper presents results of the face verification contest that was organized in conjunction with International Conference on Pattern Recognition 2000 [14]. Participants had to use identical data sets from a large, publicly available multimodal database XM2VTSDB. Training and evaluation was carried out according to an a priori known protocol ([7]). Verification results of all tested algorithms have been collected and made public on the XM2VTSDB website [15], facilitating large scale experiments on classifier combination and fusion. Tested methods included, among others, representatives of the most common approaches to face verification - elastic graph matching, Fisher's linear discriminant and Support vector machines.
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| 10. |
- Morren, Geert, et al.
(författare)
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Anatomy of the anal canal and perianal structures as defined by phased-array magnetic resonance imaging
- 2001
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Ingår i: British Journal of Surgery. - : Oxford University Press (OUP). - 0007-1323 .- 1365-2168. ; 88:11, s. 1506-1512
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Tidskriftsartikel (refereegranskat)abstract
- Background:The anatomy of the anal canal and perianal structures has been imaged using endoluminal magnetic resonance imaging (MRI). Phased-array MRI avoids the use of an endoluminal coil that may distort anatomy. The aim of this study was to describe the anatomy of the anal canal and perianal structures using phased-array MRI.Methods:Imaging was performed in 14 men and 19 nulliparous women. The dimensions of the anal canal, puborectalis, external anal sphincter, perineal body, superficial transverse perineal muscle, bulbospongiosus, ischiocavernosus and anococcygeal body were measured in different planes, and sex differences were calculated.Results:The lateral canal was significantly longer than its anterior and posterior part (P < 0·001). The anterior external anal sphincter was shorter in women than in men (P = 0·01) and occupied, respectively, 30 and 38 per cent of the anal canal length (P = 0·001). The caudal ends of the external anal sphincter formed a double layer. The perineal body was thicker in women than in men (P < 0·001) and easier to define. The superficial transverse muscles had a lateral and caudal extension to the ischiopubic bones. The bulbospongiosus was thicker in men than in women (P < 0·001). The ischiocavernosus and anococcygeal body had the same dimensions in both sexes.Conclusion:Phased-array MRI is a non-invasive technique that allows an accurate description of the normal anatomy of the anal canal and perianal structures.
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