| 1. |
- Aradi, B., et al.
(författare)
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Impurity-controlled dopant activation : Hydrogen-determined site selection of boron in silicon carbide
- 2001
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 79:17, s. 2746-2748
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Tidskriftsartikel (refereegranskat)abstract
- The geometry and formation energy of substitutional B and Al dopants as well as their complexes with hydrogen have been calculated in 4H-SiC using first-principles methods. Our results show that boron selecting the silicon site and, therefore, getting activated as a shallow acceptor depends on the presence of hydrogen which is promoted into the crystal by boron itself. Without hydrogen, boron would mostly be incorporated at the carbon site. Aluminum does not show this behavior: it always selects the silicon site and is incorporated independently of hydrogen. © 2001 American Institute of Physics.
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| 2. |
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| 3. |
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| 4. |
- Gali, A., et al.
(författare)
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Ab initio supercell calculations on aluminum-related defects in SiC
- 2007
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Ingår i: Physical Review B. Condensed Matter and Materials Physics. - 1098-0121 .- 1550-235X. ; 75:4
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Tidskriftsartikel (refereegranskat)abstract
- Ab initio supercell calculations of the binding energies predict complex formation between aluminum and carbon interstitials in SiC. In high-energy implanted SiC aluminum acceptor can form very stable complexes with two carbon interstitials. We also show that carbon vacancy can be attached to shallow aluminum acceptor. All of these defects produce deep levels in the band gap. The possible relation of these defects to the recently found aluminum-related deep-level transient spectroscopy centers is discussed. © 2007 The American Physical Society.
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| 5. |
- Gali, Adam, et al.
(författare)
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Anti-site pair in SiC : A model of the DI center
- 2003
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Ingår i: Physica B. - : Elsevier BV. ; , s. 175-179
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Konferensbidrag (refereegranskat)abstract
- The DI low-temperature photoluminescence center is a well-known defect stable up to 1700°C annealing in SiC, still its structure is not known after decades of study. Combining experimental and theoretical studies in this paper we will show that the properties of an anti-site pair can reproduce the measured one-electron level position and local vibration modes of the D I center and the model is consistent with other experimental findings as well. We give theoretical values of the hyperfine constants of the anti-site pair in its paramagnetic state as a means to confirm our model. © 2003 Elsevier B.V. All rights reserved.
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| 6. |
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| 7. |
- Ivanov, I. G., et al.
(författare)
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Investigation of intrinsic carbon-related defects in 4H-SiC by selective-excitation photoluminescence spectroscopy
- 2012
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Ingår i: Materials Science Forum Vols 717 - 720. - : Trans Tech Publications Inc.. ; , s. 259-262
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Konferensbidrag (refereegranskat)abstract
- Emission of carbon-related defects is investigated by means of selectively-excited photoluminescence in high purity 4H-SiC electron-irradiated with very low dose. Two new centers with clearly associated phonon replicas are observed, one of which is tentatively assigned to the carbon split interstitial at the hexagonal site. The temperature dependence of the spectrum is also studied and indicates that at least some of the observed luminescence lines arise from recombination of excitons bound to isoelectronic centers.
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| 8. |
- Ivanov, Ivan Gueorguiev, et al.
(författare)
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Ionization energy of the phosphorus donor in 3C-SiC from the donor-acceptor pair emission
- 2010
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Ingår i: JOURNAL OF APPLIED PHYSICS. - : American Institute of Physics. - 0021-8979 .- 1089-7550. ; 108:6, s. 063532-
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Tidskriftsartikel (refereegranskat)abstract
- Donor-acceptor pair luminescence of P-Al and N-Al pairs in 3C-SiC is analyzed. The structures in the spectra corresponding to recombination of pairs at intermediate distances are fitted with theoretical spectra of type I (P-Al pairs) and type II (N-Al pairs). It is shown that in the regions chosen for fitting the line positions obey the equation (h) over bar omega(R)=E-G-E-D-E-A+e(2)/epsilon R, where (h) over bar omega(R) is the energy of the photon emitted by recombination of a pair at a distance R, e is the electron charge, epsilon is the static dielectric constant, and E-G, E-D, and E-A are the electronic band gap and the donor and acceptor ionization energies, respectively. The fits yield the values E-G-E-D-E-A for the N-Al (2094 meV) and P-Al (2100.1 meV) cases. Using the known value of the nitrogen ionization energy, 54.2 meV, phosphorus ionization energy of 48.1 meV is obtained. Identification of the sharp lines corresponding to recombination of close pairs in the P-Al spectrum is suggested.
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| 9. |
- Virojanadara, Chariya, et al.
(författare)
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Electronic and atomic structure of the 4 H-SiC (1 over(1, ¯) 0 2) -c (2 × 2) surface
- 2008
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Ingår i: Surface Science. - : Elsevier BV. - 0039-6028 .- 1879-2758. ; 602:2, s. 525-533
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Tidskriftsartikel (refereegranskat)abstract
- The (1 over(1, ¯) 0 2) orientated plane of hexagonal silicon carbide of the 4H polytype consists of a periodic arrangement of stripes with alternating bond configuration on a nanometer scale. The two stripe configurations of the bulk truncated surface have an atomic structure very close to the carbon-face SiC basal plane and the cubic SiC(1 0 0) surface, respectively. The structural and electronic properties of the c(2 × 2) reconstruction on the 4 H-SiC (1 over(1, ¯) 0 2) surface were investigated using photoemission spectroscopy (PES), scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED). The core level photoemission spectra reveal two surface shifted Si2p components and one shifted C1s component in addition to the SiC bulk peaks. In accordance with the periodicity observed in LEED, atomically resolved STM micrographs show a c(2 × 2) arrangement of bright features which are accounted as Si adatoms. The electronic structure of this SiC (1 over(1, ¯) 0 2) -c (2 × 2) phase is experimentally determined by angle resolved PES studies of the valence band revealing four surface states. Based on the experimental observations and a comparison to similar phases on other SiC surfaces, a tentative surface model can be developed which consists of Si adatoms in so-called H3 sites on the basal-plane type stripes and carbon dimers in Si bridging configuration on the cubic stripes of the bulk truncated surface. © 2007 Elsevier B.V. All rights reserved.
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| 10. |
- Virojanadara, Chariya, et al.
(författare)
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Silicon adatom chains and one-dimensionally confined electrons on 4H-SiC(1-102): The (2x1) reconstruction
- 2008
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Ingår i: Surface Science. - : Elsevier. - 0039-6028 .- 1879-2758. ; 602:22, s. 3506-3509
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Tidskriftsartikel (refereegranskat)abstract
- The electronic and atomic structure of the 4H-SiC surface was investigated. Photoemission data indicate that the surface contains about 2 Si layers on top of the bulk layers. Scanning tunneling microscopy images show that these adlayers are terminated by an ordered array of adatom chains separated by the unit cell size. An electronic surface state located at a binding energy of 0.8 eV shows one-dimensional confinement with dispersion only along the chains. Based on the experimental observations, a tentative (2 × 1) surface model is derived with the surface terminated by alternating chains of Si adatoms and Si dimers in between.
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