| 1. |
- Jones, R., et al.
(author)
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Intrinsic defects and the D1 to D4 optical bands detected in plastically deformed Si
- 2000
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 222:1, s. 133-140
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Journal article (peer-reviewed)abstract
- The properties of multi-vacancy and multi-interstitial defects that possess luminescent bands around 1 eV are reviewed. Prominent among these are the hexavacancy and tri- and tetra-self-interstitial defects. It is suggested that the formation of these defects on dislocation cores could lead to the D1 to D4 photoluminescent bands linked to dislocations in Si and SiGe.
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| 2. |
- Kordina, Olle, et al.
(author)
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Growth of SiC by "Hot-Wall" CVD and HTCVD
- 1997
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 202:1, s. 321-334
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Journal article (peer-reviewed)abstract
- A reactor concept for the growth of high-quality epitaxial SiC films has been investigated. The reactor concept is based on a hot-wall type susceptor which, due to the unique design, is very power efficient. Four different susceptors are discussed in terms of quality and uniformity of the grown material. The films are grown using the silane–propane–hydrogen system on off-axis (0001) 6H- and 4H-SiC substrates. Layers with doping levels in the low 1014 cm—3 showing strong free exciton emission in the photoluminescence spectra may readily be grown reproducibly in this system. The quality of the grown layers is also confirmed by the room temperature minority carrier lifetimes in the microsecond range and the optically detected cyclotron resonance data which give mobilities in excess of 100000 cm2/Vs at 6 K. Finally, a brief description will be given of the HTCVD technique which shows promising results in terms of high quality material grown at high growth rates.
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| 3. |
- Monemar, Bo, 1942-, et al.
(author)
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The 3.466 eV Bound Exciton in GaN
- 2001
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 228:2, s. 489-492
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Journal article (peer-reviewed)abstract
- We discuss the available optical data for the 3.466 eV bound exciton in GaN, which has been a controversial issue in the recent literature. We conclude that the experimental results are only consistent with the identification as an exciton bound at a neutral acceptor with a spin-like bound hole. The chemical identity is still not clear.
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| 4. |
- Paskov, Plamen, 1959-, et al.
(author)
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Anisotropy of the in-plane strain in GaN grown on A-plane sapphire
- 2002
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 234:3, s. 892-896
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Journal article (peer-reviewed)abstract
- A comparative study of GaN layer grown by hydride vapour phase epitaxy on A-plane sapphire before and after removal of the substrate is presented. A large anisotropy of the in-plane strain in the as-grown sample is revealed by X-ray diffraction measurements and polarized photoluminescence. The strain anisotropy is found to modify the selection rules for the transitions leading to a splitting of the optically active states of the A and B excitons. Almost complete strain relaxation and recovery of the optical isotropy in the (0001) plane is observed in the free-standing layer.
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| 5. |
- Paskov, Plamen, 1959-, et al.
(author)
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Internal structure of free excitons in GaN
- 2001
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 228:2, s. 467-470
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Journal article (peer-reviewed)abstract
- Polarized photoluminescence is used to study the fine structure of free excitons in thick GaN layers grown on differently oriented sapphire substrates. The singlet-triplet splitting of the A exciton is measured and the exchange interaction constant in GaN is determined. For the samples grown on the a-plane sapphire, splitting of the A and B excitons induced by the uniaxial in-plane stress is also observed.
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| 6. |
- Paskov, Plamen, 1959-, et al.
(author)
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Phonon-assisted photoluminescence in InGaN/GaN multiple quantum wells
- 2002
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 234:3, s. 755-758
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Journal article (peer-reviewed)abstract
- The LO-phonon sidebands of the photoluminescence in InGaN/GaN multiple quantum wells has been investigated in the temperature range from 20 to 300 K. Analysing the intensity distribution among the phonon replicas, the strength of the exciton-phonon interaction has been estimated. The Huang-Rhys factor was found to be ÿ0.3, much larger than in GaN. The enhancement has been attributed to the exciton localization on a length scale smaller than the exciton Bohr radius and to the large internal electric field, which increases the spatial separation of the electron and hole charge densities along the growth axis.
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| 7. |
- Aberg, D, et al.
(author)
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Ultra-shallow thermal donor formation in oxygen-containing ambient
- 1998
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 210, s. 527-532
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Journal article (peer-reviewed)abstract
- Czochralski-grown phosphorus-doped (approximate to 2 x 10(14) cm(-3)) silicon wafers have been annealed in nitrogen, wet nitrogen, argon, oxygen, and vacuum ambients at 470 degrees C for times up to 500 h. Sample characterization was made with capacitance-voltage, four-point probe, DLTS, thermally stimulated capacitance, admittance spectroscopy, secondary ion-mass spectrometry, and Fourier transform infrared spectroscopy. This study finds a strong relation between the previously reported ultra-shallow thermal donors (USTDs) and shallow thermal donors (STDs), and it is shown that the net concentration of thermally formed donors is independent on annealing ambient within the experimental accuracy. It was found that the majority of formed donors for long anneals consisted of either STDs or USTDs, however, it was found that oxygen-containing ambient is indispensable for forming USTDs.
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| 8. |
- Achtziger, N, et al.
(author)
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Mobility passivating effect and thermal stability of hydrogen in silicon carbide
- 1998
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In: Physica status solidi. B, Basic research. - 0370-1972 .- 1521-3951. ; 210, s. 395-399
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Journal article (peer-reviewed)abstract
- The diffusion and passivating effect of hydrogen (isotope H-2) in epitaxial p-type SiC is studied by secondary ion mass spectrometry and capacitance-voltage profiling on Schottky diodes. The incorporation of hydrogen is achieved by low-energy ion implantation. The influence of implantation energy, temperature and subsequent annealing is presented. Annealing experiments with an electric field applied reveal a reactivation of passivated accepters and a H+ ion drift at a surprisingly low temperature of 530 K.
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| 9. |
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| 10. |
- Arvanitidis, J., et al.
(author)
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Comparative Raman Study of the 1D and 2D Polymeric Phases of C60 under Pressure
- 1999
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In: Physica status solidi. B, Basic research. - : John Wiley & Sons. - 0370-1972 .- 1521-3951. ; 215:1, s. 443-448
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Journal article (peer-reviewed)abstract
- The effect of symmetry lowering on the phonon spectra as well as the pressure effects on the vibrational spectrum of polymerized C60 were studied by Raman spectroscopy. Drastic changes related to the splitting of degenerate modes of the C60 molecule were observed together with selected softening of some of them. In spite of many similarities in the Raman spectra of the one (1D) and two-dimensional (2D) polymeric forms of C60, some salient differences in the peak intensities and the appearance of complementary modes are evident. In the Raman spectrum of the 2D polymer under high pressure, new modes, which may be related to the deformations of molecular cages, appear. The observed pressure effects are reversible and the material remains stable for pressures up to 8.8 GPa.
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