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Paskova, Tanja
Alternative names
Publications (10 of 104) Show all publications
Paskova, T., Hanser, D. A. & Evans, K. R. (2010). GaN Substrates for III-Nitride Devices. Proceedings of the IEEE, 98(7), 1324-1338.
Open this publication in new window or tab >>GaN Substrates for III-Nitride Devices
2010 (English)In: Proceedings of the IEEE, ISSN 0018-9219, E-ISSN 1558-2256, Vol. 98, no 7, 1324-1338 p.Article in journal (Refereed) Published
Abstract [en]

Despite the rapid commercialization of III-nitride semiconductor devices for applications in visible and ultraviolet optoelectronics and in high-power and high-frequency electronics, their full potential is limited by two primary obstacles: i) a high defect density and biaxial strain due to the heteroepitaxial growth on foreign substrates, which result in lower performance and shortened device lifetime, and ii) a strong built-in electric field due to spontaneous and piezoelectric polarization in the wurtzite structures along the well-established [0001] growth direction for nitrides. Recent advances in the research, development, and commercial production of native GaN substrates with low defect density and high structural and optical quality have opened opportunities to overcome both of these obstacles and have led to significant progress in the development of several opto-electronic and high-power devices. In this paper, the recent achievements in bulk GaN growth development using different approaches are reviewed; comparison of the bulk materials grown in different directions is made; and the current achievements in device performance utilizing native GaN substrate material are summarized.

Place, publisher, year, edition, pages
IEEE Institute of Electrical and Electronics, 2010
Keyword
Ammonothermal growth; doping; gallium nitride (GaN); heterostructure field-effect transistor (HFET); hydride vapor phase epitaxy; laser diode (LD); light-emitting diode (LED); native substrates; point defects; Schottky diodes; solution growth; structural defects; surface orientation; thermal conductivity
National Category
Social Sciences
Identifiers
urn:nbn:se:liu:diva-58340 (URN)10.1109/JPROC.2009.2030699 (DOI)000278811800021 ()
Note
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. Tanya Paskova, Drew A. Hanser and Keith R. Evans, GaN Substrates for III-Nitride Devices, 2010, Proceedings of the IEEE, (98), 7, 1324-1338. http://dx.doi.org/10.1109/JPROC.2009.2030699 Available from: 2010-08-13 Created: 2010-08-11 Last updated: 2017-12-12
Monemar, B., Paskov, P., Pozina, G., Hemmingsson, C., Bergman, P., Amano, H., . . . Usiui, A. (2010). Mg related acceptors in GaN. In: Phys. Status Solidi C 7. Paper presented at 8th International Conference on Nitride Semiconductors (pp. 1850). .
Open this publication in new window or tab >>Mg related acceptors in GaN
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2010 (English)In: Phys. Status Solidi C 7, 2010, 1850- p.Conference paper, Published paper (Refereed)
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-65354 (URN)
Conference
8th International Conference on Nitride Semiconductors
Available from: 2011-02-04 Created: 2011-02-04 Last updated: 2015-09-22
Son, N. T., Hemmingsson, C., Morishita, N., Ohshima, T., Paskova, T., Evans, K., . . . Janzén, E. (2010). Radiation-induced defects in GaN. In: Physica Scripta, Vol. T141. Paper presented at NMR 2009 (pp. 014015). IOP Publishing.
Open this publication in new window or tab >>Radiation-induced defects in GaN
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2010 (English)In: Physica Scripta, Vol. T141, IOP Publishing , 2010, 014015- p.Conference paper, Published paper (Refereed)
Abstract [en]

Radiation-induced defects in n-type GaN irradiated by 2 MeV electrons at room temperature were studied by electron paramagnetic resonance (EPR). Four EPR spectra, labelled D1-D4, were observed in irradiated n-type GaN. The D1 spectrum is a broad line (similar to 10-12 mT in line width) with an isotropic g-value g similar to 2.03 and can be detected in all the studied samples in the temperature range of 4-300 K. The D2 centre has an electron spin S = 1/2 and shows a clear hyperfine structure due to interaction with three equivalent N-14. The g-values of the axial configuration are determined to be g(parallel to) = 2.001 and g(perpendicular to) = 1.999. On the basis of the observed hyperfine structure, formation conditions and annealing behaviour, the D2 defect was assigned to the gallium vacancy-oxygen pair in the negative charge state, (VGaON)(-).

Place, publisher, year, edition, pages
IOP Publishing, 2010
Series
PHYSICA SCRIPTA, ISSN 0031-8949
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-62774 (URN)10.1088/0031-8949/2010/T141/014015 (DOI)000284694500016 ()
Conference
NMR 2009
Available from: 2010-12-03 Created: 2010-12-03 Last updated: 2015-09-22
Paskova, T., Preble, E. A., Hanser, A. D., Evans, K. R., Kröger, R., Paskov, P., . . . Johnson, M. A. (2009). Polar and nonpolar HVPE GaN substrates: impact of doping on the structural, electrical and optical characteristics. Paper presented at International Workshop on Nitride Semiconductors (IWN2008), Montreux, Switzerland. Physica Status Solidi. C, Current topics in solid state physics, 6(2), 344-347.
Open this publication in new window or tab >>Polar and nonpolar HVPE GaN substrates: impact of doping on the structural, electrical and optical characteristics
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2009 (English)In: Physica Status Solidi. C, Current topics in solid state physics, ISSN 1610-1634, E-ISSN 1610-1642, Vol. 6, no 2, 344-347 p.Article in journal (Refereed) Published
Abstract [en]

Polar and nonpolar bulk GaN substrates with low defect density and high structural and optical quality are demonstrated. The effect of doping by silicon, oxygen and iron within moderate doping levels on the properties of the polar GaN substrates was found uncompromised, as confirmed by high resolution X-ray diffraction and low temperature photoluminescence spectroscopy. In contrast, the lattice parameters were affected significantly, which has to be considered in the subsequent homoepitaxial device growth. The boule growth and respectively the nonpolar substrate homogeneity were found to be hampered by the doping, due to surface microcracking and higher impurity incorporation, while n-type undoped nonpolar substrates were demonstrated of superior quality.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-53964 (URN)10.1002/pssc.200880912 (DOI)
Conference
International Workshop on Nitride Semiconductors (IWN2008), Montreux, Switzerland
Available from: 2010-02-17 Created: 2010-02-16 Last updated: 2017-12-12
Paskova, T., Hanser, A., Preble, E., Evans, K., Kroeger, R., Toumisto, F., . . . Monemar, B. (2008). Defect and emission distributions in bulk GaN grown in polar and nonpolar directions: a comparative analysis. In: Proceedings of SPIE - The International Society for Optical Engineering: . Paper presented at International Symposium on Integrated Optoelectronic Devices Photonics West 2008,2008 (pp. 68940D1). .
Open this publication in new window or tab >>Defect and emission distributions in bulk GaN grown in polar and nonpolar directions: a comparative analysis
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2008 (English)In: Proceedings of SPIE - The International Society for Optical Engineering, 2008, 68940D1- p.Conference paper, Published paper (Refereed)
Abstract [en]

We have investigated bulk GaN material grown by HVPE either in the conventional polar [0001] direction and subsequently sliced with nonpolar surfaces or grown in the nonpolar [11-20] direction. Spatially resolved techniques such as cathodoluminescence imaging and transmission electron microscopy, as well as profile measuring techniques such as positron annihilation spectroscopy and secondary ion mass spectroscopy were employed to directly visualize the extended structural defects, and point defect (impurity and vacancy) distributions along the growth axes. A comparative analysis of the results shows a distinctive difference in the distribution of all kind of defects along the growth axes. A significant decrease in the defect density in material grown along the polar direction, in contrast to the constant behavior of the high defect density in material grown along the nonpolar direction points out the low-defect superior quality of the former material and indicates the preferable way of producing high-quality GaN substrates with nonpolar surfaces.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-42156 (URN)10.1117/12.767628 (DOI)60918 (Local ID)60918 (Archive number)60918 (OAI)
Conference
International Symposium on Integrated Optoelectronic Devices Photonics West 2008,2008
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2014-08-22
Tuomisto, F., Mäki, J., Pusa, P., Räisänen, J., Paskova, T., Valcheva, E. & Monemar, B. (2008). Evolution of vacancy defects in GaN after H implantation and subsequent annealing. In: IWN 2008,2008. .
Open this publication in new window or tab >>Evolution of vacancy defects in GaN after H implantation and subsequent annealing
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2008 (English)In: IWN 2008,2008, 2008Conference paper, Published paper (Refereed)
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-44200 (URN)76027 (Local ID)76027 (Archive number)76027 (OAI)
Available from: 2009-10-10 Created: 2009-10-10
Paskov, P., Monemar, B., Paskova, T., Preble, E., Hanser, A. & Evans, K. (2008). Optical characterization of bulk GaN substrates with c-, a-, and m-plane surfaces. Paper presented at IWN 2008. .
Open this publication in new window or tab >>Optical characterization of bulk GaN substrates with c-, a-, and m-plane surfaces
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2008 (English)Conference paper, Published paper (Refereed)
Series
Phys. Stat. Sol. (c) Vol. 6
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-44202 (URN)76029 (Local ID)76029 (Archive number)76029 (OAI)
Conference
IWN 2008
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2010-02-15
Darakchieva, V., Paskova, T. & Schubert, M. (2008). Optical phonons in a-plane GaN under anisotropic strain (1ed.). In: Tanya Paskova (Ed.), Group-III nitrides with nonpolar surfaces: growth, properties and devices: (pp. 219-253). Wiley.
Open this publication in new window or tab >>Optical phonons in a-plane GaN under anisotropic strain
2008 (English)In: Group-III nitrides with nonpolar surfaces: growth, properties and devices / [ed] Tanya Paskova, Wiley , 2008, 1, 219-253 p.Chapter in book (Other academic)
Abstract [en]

This is the first monograph to discuss in detail the current stage of development of nonpolar nitrides, with specific emphasis on the three main topics of crystal growth, properties and device studies. World–class researchers summarize their own recent achievements in their respective fields of expertise, covering both nonpolar and semipolar nitride materials. The bulk of the discussion in each chapter is related to the physical properties of the material obtained by the respective technique, in particular, defect density and properties of the defects in nonpolar nitrides. In addiiton, the optical and vibrational properties are also addressed in several chapters, as is progress in heterostructures, quantum wells and dots based on the AlGaN/GaN and the InGaN/GaN systems. Finally, an outlook of the application areas of the differently grown materials is presented in most chapters, together with the capabilities and limitations of the respective growth approaches used.

Place, publisher, year, edition, pages
Wiley, 2008 Edition: 1
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-42411 (URN)63799 (Local ID)978-35-2740-768-2 (ISBN)3-527-40-768-5 (ISBN)63799 (Archive number)63799 (OAI)
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2013-05-24Bibliographically approved
Paskov, P., Monemar, B., Paskova, T., Kamiyama, S., Amano, H. & Akasaki, I. (2008). Photoluminescence study of near-surface GaN/AlN superlattices. In: Proceedings of SPIE - The International Society for Optical Engineering: . Paper presented at International Symposium on Integrated Optoelectronic Devices Photonics West 2008,2008 (pp. 68940G1). .
Open this publication in new window or tab >>Photoluminescence study of near-surface GaN/AlN superlattices
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2008 (English)In: Proceedings of SPIE - The International Society for Optical Engineering, 2008, 68940G1- p.Conference paper, Published paper (Refereed)
Abstract [en]

We report on the emission properties of GaN/AlN superlattices (SLs) grown by metalorganic chemical vapor deposition on a thick GaN layer. Nominally undoped and Si-doped SL structures with the well/barrier thickness ratio 3:1 and different SL periods are investigated. It is found that in these SLs without capping layer the energy position, intensity and linewidth of the emission are determined by the interplay of the built-in polarization field, the depletion field arising from the pinning of the Fermi level at the surface, and the screening of the electric field in the quantum well due to the both the polarization-induced two-dimension electron gas (2DEG) and the photo-generated carriers. A non-uniform equilibrium electron distribution and an electron accumulation at the bottom AlN/GaN interface are evidenced by the observed recombination of the 2DEG with the photo-excited holes occurring below the GaN bandgap.

National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-42157 (URN)10.1117/12.759452 (DOI)60933 (Local ID)60933 (Archive number)60933 (OAI)
Conference
International Symposium on Integrated Optoelectronic Devices Photonics West 2008,2008
Available from: 2009-10-10 Created: 2009-10-10 Last updated: 2014-08-22
Monemar, B., Paskov, P., Pozina, G., Bergman, P., Hemmingsson, C., Toropov, A., . . . Paskova, T. (2008). Properties of dopants and defects in GaN from bound exciton spectra. In: Meijo International Symposium on Nitride Semiconductors 2008,2008. .
Open this publication in new window or tab >>Properties of dopants and defects in GaN from bound exciton spectra
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2008 (English)In: Meijo International Symposium on Nitride Semiconductors 2008,2008, 2008Conference paper, Published paper (Other academic)
National Category
Natural Sciences
Identifiers
urn:nbn:se:liu:diva-44184 (URN)75979 (Local ID)75979 (Archive number)75979 (OAI)
Note
INVITED TALKAvailable from: 2009-10-10 Created: 2009-10-10 Last updated: 2015-09-22
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