| 1. |
- Leon, R., et al.
(författare)
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Effects of proton irradiation on luminescence emission and carrier dynamics of self-assembled III-V quantum dots
- 2002
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Ingår i: IEEE Transactions on Nuclear Science. - 0018-9499 .- 1558-1578. ; 49:6, s. 2844-2851
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Tidskriftsartikel (refereegranskat)abstract
- The effects of proton irradiation (1.5 MeV) on photoluminescence intensities and carrier dynamics were compared between III-V quantum dots and similar quantum well structures. A significant enhancement in radiation tolerance is seen with three-dimensional (3-D) quantum confinement.. Measurements were carried out in different quantum dot (QD) structures, varying in material (InGaAs/GaAs and InAlAS/AlGaAS), QD surface density (4 x 10(8) to 3 x 10(10) cm(-2)), and substrate orientation [(100) and (311) B]. Similar trends were observed for all QD samples. A slight increase in PL emission after low to intermediate proton doses, are also observed in InGaAs/GaAs (100) QD structures. The latter is explained in terms of more efficient carrier transfer from the wetting layer via radiation-induced defects.
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| 2. |
- Marcinkevicius, Saulius, et al.
(författare)
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Changes in carrier dynamics induced by proton irradiation in quantum dots
- 2002
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Ingår i: Physica. B, Condensed matter. - 0921-4526 .- 1873-2135. ; 314:04-jan, s. 203-206
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Tidskriftsartikel (refereegranskat)abstract
- The effects of proton irradiation on carrier dynamics were investigated by time-resolved photoluminescence on different InGaAs/GaAs quantum-dot (QD) structures varying in QD surface density and substrate orientation, as well as thin InGaAs quantum wells. The carrier lifetimes in the dots are much less affected by proton irradiation than in the wells. Decrease in lifetimes of only 40 percent at the highest proton dose are observed in some of the QDs, whereas an similar to20 to similar to40-fold decrease is observed in the wells. Similar trends were observed for all quantum dot samples.
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| 3. |
- Marcinkevičius, Saulius, et al.
(författare)
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Changes in luminescence intensities and carrier dynamics induced by proton irradiation in In_xGa_1-xAs/GaAs quantum dots
- 2002
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 66:23, s. 235314-
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Tidskriftsartikel (refereegranskat)abstract
- The effects of proton irradiation (1.5 MeV) on photoluminescence intensities and carrier dynamics were compared between InGaAs/GaAs quantum dots and similar quantum well structures. A significant enhancement in radiation tolerance is seen with three-dimensional quantum confinement. Measurements were carried out in different quantum dot structures varying in dot surface density (4x10(8)-3x10(10) cm(-2)) and substrate orientation [(100) and (311)B]. Similar trends were observed for all quantum dot samples. A slight increase in photoluminescence emission intensity after low to intermediate proton doses is observed in InGaAs/GaAs (100) quantum dot structures. The latter is explained in terms of more efficient carrier transfer from the wetting layer via radiation-induced defects.
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| 4. |
- Suchodolskis, A., et al.
(författare)
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Pseudogap structure in icosahedral ZnMgY and ZnMgHo quasicrystals
- 2003
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Ingår i: Applied Surface Science. - 0169-4332 .- 1873-5584. ; 212, s. 485-490
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Tidskriftsartikel (refereegranskat)abstract
- The results of a photoemission study of icosahedral single-grain ZnMg(Y, Ho) quasicrystals and their crystalline approximant Zn2Mg are presented. Synchrotron radiation photoemission measurements have been performed on in situ cleaved samples at low temperature of approximate to90 K and 10(-10) mbar pressure. The spectra obtained indicate simple metal-type valence bands (VB) with distinct Fermi edge cutoff. Analysis of the Fermi edge spectra reveals the presence of a pseudogap in i-ZnMg(Y, Ho) quasicrystals. The pseudogap corresponds to a rather sharp DOS dip at the Fermi level with th approximate to50% (of the normal DOS) depth and the approximate to0.8 eV width. The values of i-ZnMg(Y, Ho) pseudogap parameters are comparable with those of other quasicrystals.
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