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Wagner, Matthias
Publications (10 of 24) Show all publications
Nguyen, S. T., Wagner, M., Hemmingsson, C., Storasta, L., Magnusson, B., Chen, W., . . . Janzén, E. (2004). Electronic structure of deep defects in SiC. In: W.J. Choyke, H. Matsunami, G. Pens (Ed.), Silicon Carbide: Recent Major Advances: . Berlin, Heidelberg: Springer Verlag
Open this publication in new window or tab >>Electronic structure of deep defects in SiC
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2004 (English)In: Silicon Carbide: Recent Major Advances / [ed] W.J. Choyke, H. Matsunami, G. Pens, Berlin, Heidelberg: Springer Verlag , 2004, p. -899Chapter in book (Other academic)
Abstract [en]

Since the 1997 publication of Silicon Carbide - A Review of Fundamental Questions and Applications to Current Device Technology edited by Choyke, et al., there has been impressive progress in both the fundamental and developmental aspects of the SiC field. So there is a growing need to update the scientific community on the important events in research and development since then. The editors have again gathered an outstanding team of the world's leading SiC researchers and design engineers to write on the most recent developments in SiC. The book is divided into five main categories: theory, crystal growth, characterization, processing and devices. Every attempt has been made to make the articles as up-to-date as possible and assure the highest standards of accuracy. As was the case for earlier SiC books, many of the articles will be relevant a decade from now so that this book will take its place next to the earlier work as a permanent and essential reference volume.

Place, publisher, year, edition, pages
Berlin, Heidelberg: Springer Verlag, 2004
Series
Advanced texts in physics, ISSN 1439-2674
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-45173 (URN)79898 (Local ID)978-3-540-40458-3 (ISBN)3-540-40458-9 (ISBN)79898 (Archive number)79898 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2015-09-22Bibliographically approved
Wagner, M., Ivanov, I. G., Storasta, L., Bergman, J., Magnusson, B., Chen, W. & Janzén, E. (2003). Photoluminescence up-conversion processes in SiC. In: Materials Science Forum, Vols. 433-436. Paper presented at ECSCRM2002 (pp. 309-312). , 433-4
Open this publication in new window or tab >>Photoluminescence up-conversion processes in SiC
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2003 (English)In: Materials Science Forum, Vols. 433-436, 2003, Vol. 433-4, p. 309-312Conference paper, Published paper (Refereed)
Abstract [en]

Efficient photoluminescence up-conversion is observed in 4H SiC samples containing both the UD-3 defect with its characteristic photoluminescence (PL) no-phonon (NP) line in the near infrared at 1.356 eV and the titanium impurity with its emission in the visible spectral region. When both defects are present, the titanium emission can be excited efficiently by tuning the laser to UD-3. In 4H samples containing either only UD-3 or only titanium, a different photoluminescence up-conversion process can be observed. This second process occurs at photon energies higher than approximately 1.5 eV without exhibiting a clear threshold. In 6H and 15R SiC only this second process was found, even when both the UD-3 defect and the titanium impurity are abundant.

Keywords
deep level, photoluminescence up-conversion, semi-insulating
National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-48542 (URN)
Conference
ECSCRM2002
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2013-10-02
Wagner, M., Magnusson, B., Chen, W. & Janzén, E. (2002). Electronic structure of the UD3 defect in 4H and 6H SiC. In: Materials Science Forum, Vols. 389 - 393: . Paper presented at ICSCRM2001 (pp. 509). Trans Tech Publications, Switzerland
Open this publication in new window or tab >>Electronic structure of the UD3 defect in 4H and 6H SiC
2002 (English)In: Materials Science Forum, Vols. 389 - 393, Trans Tech Publications, Switzerland , 2002, p. 509-Conference paper, Published paper (Refereed)
Place, publisher, year, edition, pages
Trans Tech Publications, Switzerland, 2002
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-45091 (URN)10.4028/www.scientific.net/MSF.389-393.509 (DOI)79657 (Local ID)79657 (Archive number)79657 (OAI)
Conference
ICSCRM2001
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-03-12
Wagner, M., Thinh, N., Nguyen, T. S., Chen, W., Janzén, E., Baranov, P., . . . Lindstrom, J. (2002). Ligand hyperfine interaction at the neutral silicon vacancy in 4H- and 6H-SiC. Physical Review B. Condensed Matter and Materials Physics, 66(15)
Open this publication in new window or tab >>Ligand hyperfine interaction at the neutral silicon vacancy in 4H- and 6H-SiC
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2002 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 66, no 15Article in journal (Refereed) Published
Abstract [en]

The silicon vacancy in its neutral charge state (V-Si) has been unambiguously identified in 4H- and 6H-SiC. This was achieved by observation of ligand hyperfine interaction with the four carbon atoms in the nearest-neighbor shell and the twelve silicon atoms in the next-nearest-neighbor shell surrounding the vacancy. The complete hyperfine tensors have been determined for the V-Si(0) center residing at all inequivalent lattice sites in the two polytypes. These are compared with the parameters previously obtained for the negatively charged silicon vacancy.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-47841 (URN)10.1103/PhysRevB.66.155214 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Wagner, M., Ivanov, I. G., Storasta, L., Bergman, P., Magnusson, B., Chen, W. & Janzén, E. (2002). Photoluminescence upconversion in 4H-SiC. Applied Physics Letters, 81(14), 2547
Open this publication in new window or tab >>Photoluminescence upconversion in 4H-SiC
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2002 (English)In: Applied Physics Letters, ISSN 0003-6951, E-ISSN 1077-3118, Vol. 81, no 14, p. 2547-Article in journal (Refereed) Published
Abstract [en]

 Efficient photoluminescence upconversion is observed in 4H-SiC samples containing both the UD-3 defect and the titanium impurity. In this process, the titanium photoluminescence emission with no-phonon (NP) lines at 2.848 eV (A0) and 2.789 eV (B0) can be excited by tuning the laser to the NP line of UD-3 at 1.356 eV. In samples containing either only UD-3 or only titanium, a different photoluminescence upconversion process can be observed, which occurs at photon energies higher than ~1.5 eV without exhibiting sharp features. At least one of the two processes generates both free electrons and free holes and can, therefore, be a candidate for an important recombination channel.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-45079 (URN)10.1063/1.1511813 (DOI)79596 (Local ID)79596 (Archive number)79596 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Wagner, M., Thinh, N., Son, N. T., Baranov, P., Mokhov, E., Hallin, C., . . . Janzén, E. (2002). The neutral silicon vacancy in SiC: Ligand hyperfine interaction. In: Materials Science Forum, Vols. 389-393. Paper presented at ICSCRM2001 (pp. 501-504). , 389-3
Open this publication in new window or tab >>The neutral silicon vacancy in SiC: Ligand hyperfine interaction
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2002 (English)In: Materials Science Forum, Vols. 389-393, 2002, Vol. 389-3, p. 501-504Conference paper, Published paper (Refereed)
Abstract [en]

The isolated silicon vacancy in its neutral charge state has unambiguously been confirmed in electron irradiated 4H and 6H SiC. This was achieved by the observation of the ligand hyperfine lines arising from interaction with C-13 atoms in the nearest-neighbor (NN) shell and With Si-29 atoms in the next-nearest-neighbor (NNN) shell in optically detected magnetic resonance (ODMR) experiments. The complete hyperfine tensors for all inequivalent lattice sites have been deduced and are compared to the known hyperfine parameters for the negatively charged silicon vacancy in the two polytypes.

Keywords
electron irradiation, ligand hyperfine interaction, ODMR, silicon vacancy
National Category
Engineering and Technology Condensed Matter Physics
Identifiers
urn:nbn:se:liu:diva-48808 (URN)10.4028/www.scientific.net/MSF.389-393.501 (DOI)
Conference
ICSCRM2001
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2013-10-02
Wagner, M., Magnusson, B., Chen, W. & Janzén, E. (2002). UD-3 defect in 4H, 6H, and 15R SiC: Electronic structure and phonon coupling. Physical Review B. Condensed Matter and Materials Physics, 66(11)
Open this publication in new window or tab >>UD-3 defect in 4H, 6H, and 15R SiC: Electronic structure and phonon coupling
2002 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, E-ISSN 1550-235X, Vol. 66, no 11Article in journal (Refereed) Published
Abstract [en]

The UD-3 photoluminescence (PL) spectrum is observed in high-resistive or semi-insulating bulk 4H, 6H, and 15R SiC. It consists of one no-phonon (NP) line in 4H and 6H SiC and two NP lines in 15R SiC. The line positions are 1.3555 eV in 4H SiC, 1.3440 eV in 6H SiC and 1.3474 eV (UD-3(L)) and 1.3510 eV (UD-3(H)) in 15R SiC. In PL excitation experiments, an additional set of four lines (UD-3(I)-UD-3(IV)) is observed in all three polytypes. The symmetry of the ground state and the excited states involved in these transitions is determined from Zeeman and polarization experiments. The NP line is accompanied by a broad phonon assisted side band. In addition, three sharp transitions UD-3(a), UD-3(b), and UD-3(c) and three broader features have been observed. These are assigned to local phonons.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:liu:diva-47848 (URN)10.1103/PhysRevB.66.115204 (DOI)
Available from: 2009-10-11 Created: 2009-10-11 Last updated: 2017-12-13
Toropov, A. A., Sorokin, S. V., Kuritsyn, K. A., Ivanov, S. V., Pozina, G., Bergman, P., . . . Landwehr, G. (2001). Magneto-photoluminescence studies of Cd(Mn)Se/Zn(Mn)Se diluted magnetic nanostructures. Physica. E, Low-Dimensional systems and nanostructures, 10(1-3), 362-367
Open this publication in new window or tab >>Magneto-photoluminescence studies of Cd(Mn)Se/Zn(Mn)Se diluted magnetic nanostructures
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2001 (English)In: Physica. E, Low-Dimensional systems and nanostructures, ISSN 1386-9477, E-ISSN 1873-1759, Vol. 10, no 1-3, p. 362-367Article in journal (Refereed) Published
Abstract [en]

We report on cw and time-resolved photoluminescence (PL) studies of Cd(Mn)Se/Zn(Mn)Se diluted magnetic semiconductor nanostructures grown by molecular beam epitaxy. Excitonic PL intensity, decay time and Zeeman splitting have been studied systematically as a function of Cd(Mn)Se nominal thickness, Mn concentration and sample design. Wave function mapping has been performed, evidencing the formation of semi-magnetic quantum disk islands in the samples with thick enough Cd(Mn)Se insertions. ⌐ 2001 Elsevier Science B.V.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-45108 (URN)10.1016/S1386-9477(01)00117-5 (DOI)79717 (Local ID)79717 (Archive number)79717 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-12-13
Wagner, M., Magnusson, B., Chen, W., Janzén, E., Sörman, E., Hallin, C. & Lindström, J. L. (2000). Electronic structure of the neutral silicon vacancy in 4H and 6H SiC. Physical review. B, Condensed matter and materials physics, 62(24), 16555-16560
Open this publication in new window or tab >>Electronic structure of the neutral silicon vacancy in 4H and 6H SiC
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2000 (English)In: Physical review. B, Condensed matter and materials physics, ISSN 2469-9950, Vol. 62, no 24, p. 16555-16560Article in journal (Refereed) Published
Abstract [en]

 Detailed information about the electronic structure of the lowest-lying excited states and the ground state of the neutral silicon vacancy in 4H and 6H SiC has been obtained by high-resolution photoluminescence (PL), PL excitation (PLE), and Zeeman spectroscopy of both PL and PLE. The excited states and the ground states involved in the characteristic luminescence of the defect with no-phonon (NP) lines at 1.438 and 1.352 eV in 4H SiC and 1.433, 1.398, and 1.368 eV in 6H SiC are shown to be singlets. The orbital degeneracy of the excited states is lifted by the crystal field for the highest-lying NP lines corresponding to one of the inequivalent lattice sites in both polytypes, leading to the appearance of hot lines at slightly higher energies. Polarization studies of the NP lines show a different behavior for the inequivalent sites. A comparison of this behavior in the two polytypes together with parameters from spin resonance studies provides useful hints for the assignment of the no-phonon lines to the inequivalent sites. In strained samples an additional fine structure of the NP lines can be resolved. This splitting may be due to strain variations in the samples.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-45137 (URN)10.1103/PhysRevB.62.16555 (DOI)79790 (Local ID)79790 (Archive number)79790 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2018-05-21
Chen, W., Buyanova, I., Sörman, E., Hai, P. N., Wagner, M., Janzén, E. & Monemar, B. (2000). Magneto-optical spectroscopy of defects in wide bandgap semiconductors: GaN and SiC. In: Proceedings Conference on Optoelectronic and Microelectronic Materials and Devices: . Paper presented at Conference on Optoelectronic and Microelectronic Materials and Devices, 6-8 December 2000, Bundoora, Vic., Australia (pp. 497-502). IEEE
Open this publication in new window or tab >>Magneto-optical spectroscopy of defects in wide bandgap semiconductors: GaN and SiC
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2000 (English)In: Proceedings Conference on Optoelectronic and Microelectronic Materials and Devices, IEEE , 2000, p. 497-502Conference paper, Published paper (Refereed)
Abstract [en]

We review recent progress in our understanding of intrinsic defects in GaN and SiC, gained from magneto-optical studies by Zeeman measurements and optically detected magnetic resonance. The two best-known intrinsic defects in these two wide bandgap semiconductors, i.e. the Ga interstitial in GaN and the silicon vacancy in SiC, are discussed in detail. The Ga interstitial is the first and only intrinsic defect in GaN that has so far been unambiguously identified, either in the presumably isolated form or in a family of up to three complexes. The silicon vacancy is among the most studied intrinsic defect in SiC, at least in two charge states, and yet still remains controversial.

Place, publisher, year, edition, pages
IEEE, 2000
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-45113 (URN)10.1109/COMMAD.2000.1022997 (DOI)79722 (Local ID)0-7803-6698-0 (ISBN)79722 (Archive number)79722 (OAI)
Conference
Conference on Optoelectronic and Microelectronic Materials and Devices, 6-8 December 2000, Bundoora, Vic., Australia
Note

INVITED TALK

Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2017-03-27
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