Investigation of point defects in wide band gap materials by methods beyond the standard density functional theory  Page description

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Details of project

  
Identifier
67886
Type K
Principal investigator Gali, Ádám
Title in Hungarian Ponthibák vizsgálata széles tiltott sávú anyagokban a standard sűrűségfunkcionál elméleteken túli módszerekkel
Title in English Investigation of point defects in wide band gap materials by methods beyond the standard density functional theory
Keywords in Hungarian ponthibák, kvantummechanikai számítások, sűrűségfunkcionál-elmélet
Keywords in English point defects, quantum mechanical calculations, density functional theory
Discipline
Solid-state Physics (Council of Physical Sciences)100 %
Panel Physics 1
Department or equivalent Department of Atomic Physics (Budapest University of Technology and Economics)
Starting date 2007-07-01
Closing date 2011-07-31
Funding (in million HUF) 7.000
FTE (full time equivalent) 1.32
state closed project
Summary in Hungarian
Szinte minden használati eszközünket és berendezésünket az elektronika vezérli. Extrém körülmények között a széles tiltottsávú anyagok jöhetnek szóba elektronikai alapanyagként. A legígéretesebb széles tiltottsávú félvezetők a szilíciumkarbid (SiC) és a galliumnitrid (GaN). Mindkét anyagban a fő problémát egyelőre a növesztésben vagy adalékolás során létrejött hibák jelentik. A pályázat célja az, hogy a SiC-ban és GaN-ben első elvű szupercella számítások segítségével azonosítsuk a hibákat annak érdekében, hogy megértsük a technológiai lépések során lejátszódó atomi folyamatokat. A legelterjedtebb metódus ilyen számítások elvégzésére a DFT alapú LDA/GGA módszer. Egy nagy hibája ennek a módszernek az, hogy alulbecsli a tiltottsávot, amelynek következményeként a számított hibaszintek helyzete a tiltottsávban bizonytalan, pedig az az egyik legfontosabb ujjlenyomata a hibáknak. A pályázat olyan módszerek használatát célozza meg, amelyek korrigálják ezt a tiltottsáv hibát, mint az ön-konzisztens olló-operátor, hibrid funkcionál, egyszerűsített GW közelítés és esetleg az optimált kicserélődési potenciál. A kutatást szoros nemzetközi együttműködésben végezzük mind elméleti, mind a kísérleti csoportokkal. Az eredményket közös közleményekben kívánjuk megjelentetni. A pályázati pénzből nagyteljesítményű PC-ket szeretnénk venni a számítások elvégzése céljából, valamint a konferenciautak támogatására használnánk, hogy eredményeinket megmutassuk és a személyes kapcsolatokat fenn tudjuk tartani.
Summary
Electronics penetrates into the control of all kind of equipments and of devices. In order to use electronics in extreme conditions wide band-gap materials should be used. The most promising candidates among the wide band gap semiconductors are silicon carbide (SiC) and gallium nitride (GaN). In both materials the major problem is the control of defects created during growth or doping. The goal of this proposal to identify the defects in SiC and in GaN by ab initio supercell calculations in order to understand the atomistic processes in those materials during the technological steps. The state-of-the-art methodology of these kind of calculations is the standard LDA/GGA method within DFT. One major problem of that method that it underestimates the band-gap. As a consequence, the calculated position of the defect levels in the band-gap is uncertain, which is, however, one of the main fingerprint of the defects. The proposal aims to use such methods which can correct this band-gap error, like simple self-consistent scissor-operator, and the more complicated hybrid functionals, the simplified GW approximation and possibly the optimized exchange potential. This research is bound strongly to international cooperations with both theoretical and experimental groups. The results will be published in joint papers. We would like to buy very high performance PCs to carry out the calculations and to cover the trips to international conferences from the budget of this proposal in order to show the results and to keep personal contacts.




 

Final report

  
Results in Hungarian
Tématerületek szerinti eredményeim röviden felsorolva: 1) Hibaazonosítás félvezetőkben: A szilíciumkarbidban és az alumíniumnitridben számos ponthibát sikerült azonosítanom a kísérleti csoportokkal együttműködve. 2)Spintronika, kvantumoptika: Nitrogén-vakancia a gyémántban az egyik legjelentősebb szilárdtestbeli kvantumbit. A fenti hiba gerjesztési mechanizmusát, spinsűrűség-eloszlását és számos más tulajdonságát sikerült számításaimmal megérteni. A semleges nitrogén-vakancia elektro-lumineszcencia jelét a számításaim segítségével sikerült megérteni, amelyet a Nature Photonics folyóiratban szeretnénk leközölni (bírálóknál van a kézirat). Emellett Physical Review Letters és Physical Review B Rapid Communication, valamint több meghívott szerzős cikkben közöltem eredményeimet. 3)Napelem: A napelemekkel hatásfokának lehetséges javításával kapcsolatos eredményeinket a Nano Letters közölte. Az eredményekről a Materials Research Society folyóiratában recenziót közöltek. 4)Biomarker: A biomarker témában elsősorban a SiC nanoszerkezeteket vizsgáltuk meg. Eredményeink magyarázatot adnak számos friss kísérleti tényre. Az evvel kapcsolatos eredmények az Applied Physics Letters és a The Journal of Chemical Physics folyóiratokban jelentek meg. 5) Nanoelektronika: A nanoelektronikában fontos Si nanohuzalokban egy áttöréshez vezető elrendezést vázoltunk fel, amelynek segítségével a kisméretű nanohuzalok vezetőképességét meg lehet növelni. Eredményeinket a Nano Letters folyóiratban közöltük.
Results in English
My results are briefly listed and enumerated in different fields: i) Identification of point defects in semiconductors: Numerous point defects were identified in silicon carbide and aluminum nitride in cooperation with experimental group. ii)Spintronics, quantum optics: Nitrogen-vacancy center in diamond is one of the most prominent quantum bit in solid. The mechanism of excitation, the distribution of spin density, and numerous other properties of this defect were understood by my calculations. The signal of electro-luminescence of neutral nitrogen-vacancy could be understood by the help of my calculations that we wish to publish in Nature Photonics (under referee review). Besides, my results were published in Physical Review Letter, Physical Review B Rapid Communication, and invited feature articles. iii)Photo-voltaics: Our results aout the possible increase in efficiency of solar cells were published in Nano Letters. The results were highlighted in the Bulletin of Materials Research Society in US. iv)Biomarker: We studied mostly SiC nanoparticles in the field of biomarkers. Our results could explain various recent experimental data. We published our results in Applied Physics Letters és a The Journal of Chemical Physics. v)Nanoelectronics: We proposed such a set-up for Si nanowire based nanoelectonics device where it may lead to a breakthrough in increasing the electrical conduction in ultrasmall nanowires. Our results were published in Nano Letters.
Full text https://www.otka-palyazat.hu/download.php?type=zarobeszamolo&projektid=67886
Decision
Yes





 

List of publications

  
N. Mizuochi, T. Makino, H. Kato, D. Takeuchi, M. Ogura, H. Okushi, M. Nothaft, P. Neumann, A. Gali, F. Jelezko, J. Wrachtrup, and S. Yamasaki: Electrically driven single photon source at room temperature in diamond, Nature Photonics, under referee review, 2011
Yan BH, Frauenheim T, Gali A: Gate-Controlled Donor Activation in Silicon Nanowires, NANO LETTERS 10:(9) pp. 3791-3795, 2010
Gali Adam, Vörös Márton, Rocca Dario, Zimanyi Gergely T, Galli Giulia: High-Energy Excitations in Silicon Nanoparticles, NANO LETTERS 9:(11) pp. 3780-3785, 2009
Gali A, Janzen E, Deak P, Kresse G, Kaxiras E: Theory of Spin-Conserving Excitation of the N-V- Center in Diamond, PHYSICAL REVIEW LETTERS 103:(18) p. 186404., 2009
E. Janzén, A. Gali, A. Henry, I. G. Ivanov, B. Magnusson, and N. T. Son: Defects in SiC, Defects in Microelectronic Materials and Devices, 2009
Son NT, Gali A, Szabo A, Bickermann M, Ohshima T, Isoya J, Janzen E: Defects at nitrogen site in electron-irradiated AlN, APPLIED PHYSICS LETTERS 98:(24) Paper 242116, 2011
Carlsson P, Son NT, Gali A, Isoya J, Morishita N, Ohshima T, Magnusson B, Janzen E: EPR and ab initio calculation study on the EI4 center in 4H- and 6H-SiC, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 82:(23) Paper 235203, 2010
Ma Yuchen, Rohlfing Michael, Gali Adam: Excited states of the negatively charged nitrogen-vacancy color center in diamond, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 81:(4) p. 041204(R), 2010
Voros M, Deak P, Frauenheim T, Gali A: The absorption spectrum of hydrogenated silicon carbide nanocrystals from ab initio calculations, APPLIED PHYSICS LETTERS 96:(5) p. 051909, 2010
Áron Szabó, Nguyen Tien Son, Erik Janzén, and Adam Gali: Group-II acceptors in wurtzite AlN: A screened hybrid density functional study, APPLIED PHYSICS LETTERS 96 p. 192110, 2010
Peter Deák, Bálint Aradi, Thomas Frauenheim, Erik Janzén, and Adam Gali: Accurate defect levels obtained from the HSE06 range-separated hybrid functional, Physical Review B, 81 p. 153203, 2010
Gali A, Gallstrom A, Son NT, Janzen E: Theory of neutral divacancy in SiC: a defect for spintronics, MATERIALS SCIENCE FORUM 645-648: pp. 395-397, 2010
Yan F, Devaty RP, Choyke WJ, Kimoto T, Ohshima T, Pensl G, Gali A: New lines and issues associated with deep defect spectra in electron, proton and 4He ion irradiated 4H SiC, MATERIALS SCIENCE FORUM 645-648: pp. 411-414, 2010
Knaup JM, Voros M, Deak P, Gali A, Frauenheim T, Kaxiras E: Annealing simulations to determine the matrix interface structure of SiC quantum dots embedded in SiO(2), PHYSICA STATUS SOLIDI C: CURRENT TOPICS IN SOLID STATE PHYSICS, VOL 7, NO 2., pp. 407-410., 2010
Voros M, Deak P, Frauenheim T, Gali A: The absorption of oxygenated silicon carbide nanoparticles, JOURNAL OF CHEMICAL PHYSICS 133:(6) Paper 064705, 2010
A Gali, T Simon, J E Lowther: An ab initio study of local vibration modes of the nitrogen-vacancy center in diamond, NEW JOURNAL OF PHYSICS 13:(2) Paper 025016, 2011
Benjamin Schmeltzer, Lilian Childress, Adam Gali: 13 C hyperfine interactions in the nitrogen-vacancy centre in diamond, NEW JOURNAL OF PHYSICS 13:(2) Paper 025021, 2011
Deak P, Gali A, Aradi B, Frauenheim T: Accurate gap levels and their role in the reliability of other calculated defect properties, PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 248:(4) pp. 790-798, 2011
Gali A: Defects in SIC: theory, MATERIALS SCIENCE FORUM 679-680: pp. 225-232, 2011
Vörös M, Deák P, Frauenheim T, Gali A: Influence of Oxygen on the Absorption of Silicon Carbide Nanoparticles, MATERIALS SCIENCE FORUM 679-680: pp. 520-523, 2011
Hornos T, Gali A, Svensson BG: Large-Scale Electronic Structure Calculations of Vacancies in 4H-SiC Using the Heyd-Scuseria-Ernzerhof Screened hybrid Density Functional, MATERIALS SCIENCE FORUM 679-680: p. 261-264, 2011
Gali A: Time-dependent density functional study on the excitation spectrum of point defects in semiconductors, PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS 248:(6) pp. 1337-1346, 2011
Gali Adam, Kaxiras Efthimios, Zimanyi Gergely T, Meng Sheng: Effect of symmetry breaking on the optical absorption of semiconductor nanoparticles, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 84:(3) p. 035325, 2011
Heiss Martin, Conesa-Boj Sonia, Ren Jun, Tseng Hsiang-Han, Gali Adam, Rudolph Andreas, Uccelli Emanuele, Peir oacute Francesca, Morante Joan Ramon, Schuh Dieter, Reiger Elisabeth, Kaxiras Efthimios, Arbiol Jordi, Fontcuberta i Morral Anna: Direct correlation of crystal structure and optical properties in wurtzite/zinc-blende GaAs nanowire heterostructures, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 83:(4) Paper 045303, 2011
Maze JR, Gali A, Togan E, Chu Y, Trifonov A, Kaxiras E, Lukin MD: Properties of nitrogen-vacancy centers in diamond: the group theoretic approach, NEW JOURNAL OF PHYSICS 13: Paper 025025, 2011
M. Bockstedte, A. Marini, A. Gali, Oleg Pankratov, and A. Rubio: Defects Identified in SiC and Their Implications, Mater. Sci. Forum vol. 600-603, 285-290, 2009
Janzén Erik, Gali Adam, Carlsson Patrick, Gällström Andreas, Magnusson Björn, Son N T: The silicon vacancy in SiC, Physica B, 404, 4354-4358, 2009
Riccardo Rurali, Bálint Aradi, Thomas Frauenheim, and Ádám Gali: Donor levels in Si nanowires determined by hybrid-functional calculations, Phys. Rev. B, vol. 79, 115303, 2009
T. Umeda, J. Isoya, N. Morishita, T. Ohshima, E. Janzén, and A. Gali: Dicarbon antisite defect in n-type 4H-SiC, Phys. Rev. B, vol. 79, 115211, 2009
Adam Gali: Theory of the neutral nitrogen-vacancy center in diamond and its application to the realization of a qubit, Phys. Rev. B, vol. 79, 235210, 2009
Adam Gali and Efthimios Kaxiras: Comment on "Ab Initio Electronic and Optical Properties of the (N-V)- Center in Diamond", Phys. Rev. Lett., vol. 102, 149703, 2009
E. Janzén, A. Gali, P. Carlsson, A. Gällström, B. Magnusson, N. T. Son: The Silicon Vacancy in SiC, Mater. Sci. Forum, vol. 615-617, 347-352, 2009
A. Gali, T. Umeda, E. Janzén, N. Morishita, T. Ohshima, J. Isoya: Identification of the Negative Di-Carbon Antisite Defect in n-Type 4H-SiC, Mater. Sci. Forum, vol. 615-617, 361-364, 2009
N. T. Son, J. Isoya, N. Morishita, T. Ohshima, H. Itoh, A. Gali, Erik Janzén: Defects Introduced by Electron-Irradiation at Low Temperatures in SiC, Mater. Sci. Forum, vol. 615-617, 377-380, 2009
Gali A: Identification of individual [sup 13]C isotopes of nitrogen-vacancy center in diamond by combining the polarization studies of nuclear spins and first-principles calculat, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 80:(24) p. 241204(R), 2009
Son NT, Janzen E, Isoya J, Morishita N, Hanaya H, Takizawa H, Ohshima T, Gali A: Identification of a Frenkel-pair defect in electron-irradiated 3C SiC, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 80:(12) p. 125201, 2009
Szabo A, Gali A: Effect of oxygen on single-wall silicon carbide nanotubes studied by first-principles calculations, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 80:(7) p. 075425, 2009
Voros M, Gali A: Optical absorption of diamond nanocrystals from ab initio density-functional calculations, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 80:(16) p. 161411(R), 2009
Ádám Gali, Michel Bockstedte, Ngyen Tien Son, Erik Janzén: Point Defects in SiC: Point Defects in SiC, Silicon Carbide 2008 - Materials, Processing and Devices, (Mater. Res. Soc. Symp. Proc. Volume 1069, Warrendale, PA, 2008), 1069-D03-01, 2008
Peter Deák, Bálint Aradi, Thomas Frauenheim, and Adam Gali: Challenges for ab initio defect modeling, Materials Science and Engineering B, vol. 154-155, 187-192, 2008
Michel Bockstedte, Adam Gali, Alexander Mattausch, Oleg Pankratov, and John W. Steeds: Identification of intrinsic defects in SiC: Towards an understanding of defect aggregates by combining theoretical and experimental approaches, Physica Status Solidi (b) vol. 245, 1281, 2008
Hornos T, Son NT, Janzen E, Gali A: Theoretical study of small silicon clusters in 4H-SiC, PHYSICAL REVIEW B CONDENSED MATTER AND MATERIALS PHYSICS 76:(16) p. 165209., 2007



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