Papers by Author: Adam Gali

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Authors: Peter Deák, Adam Gali, Z. Hajnal, Thomas Frauenheim, Nguyen Tien Son, Erik Janzén, Wolfgang J. Choyke, P. Ordejón
Authors: Peter Deák, B. Aradi, Adam Gali, Uwe Gerstmann, Wolfgang J. Choyke
Authors: T. Hornos, Adam Gali, Nguyen Tien Son, Erik Janzén
Abstract: We have investigated several aluminum-related complexes in 4H-SiC by ab initio supercell calculations. The binding energies of the defects predict high thermal stability and complex formation between aluminum and carbon interstitials in SiC. We show that the carbon vacancy can be attached to a shallow the aluminum acceptor and form a very stable defect. We also found that aluminum interstitial forms stable and metastable complexes with one or two carbon interstitials. The possible relation of these defects to the recently found aluminum- related DLTS centers is also discussed.
Authors: T. Hornos, Adam Gali, Robert P. Devaty, Wolfgang J. Choyke
Abstract: Ab initio supercell calculations have been carried out to investigate the doping of phosphorus in chemical vapor deposited (CVD) SiC layers. CVD conditions have been simulated by using the appropriate chemical potentials for hydrogen and phosphorus (P). We found that the most abundant defect is P at Si-site followed by P at C-site. The calculated concentrations of the P-donors and free carriers in CVD grown SiC agree with the experimental results.
Authors: Adam Gali, Peter Deák, E. Rauls, P. Ordejón, F.H.C. Carlsson, Ivan G. Ivanov, Nguyen Tien Son, Erik Janzén, Wolfgang J. Choyke
Authors: B. Aradi, Adam Gali, Peter Deák, E. Rauls, Thomas Frauenheim, Nguyen Tien Son
Authors: Adam Gali, Peter Deák, Nguyen Tien Son, Erik Janzén, Hans Jürgen von Bardeleben, Jean-Louis Monge
Authors: M. Bockstedte, A. Marini, Adam Gali, Oleg Pankratov, A. Rubio
Abstract: Defect signatures, such as deep level positions, hyperfine parameters, local vibrational modes and optical transitions characterize a defect and enable the identification of defect centers. This identification is a key to an understanding of complex phenomena like the defect kinetics. Albeit density functional theory enabled the identification of several defects and their kinetic properties, a new approach is needed to address the optical excitation of defect. Within a quasiparticle theory and taking into account excitonic effects we analyze the excited states of VC +.
Authors: Adam Gali
Abstract: A brief overview about the recent progress in developing the methods to calculate the properties of defects in solids is given and some recent examples on vacancy-related defects in SiC are presented.
Authors: Nguyen Tien Son, Junichi Isoya, Norio Morishita, Takeshi Ohshima, Hisayoshi Itoh, Adam Gali, Erik Janzén
Abstract: Defects introduced by electron irradiation at ~80-100 K in 3C-, 4H- and 6H-SiC were studied by electron paramagnetic resonance (EPR). A number of EPR spectra, labelled LE1-10, were detected. Combining EPR and supercell calculations, we will show that the LE1 center in 3C-SiC with C2v symmetry and an electron spin S=3/2 is related to the (VSi-Sii)3+ Frenkel pair between the silicon vacancy and a second neighbour Sii interstitial along the <100> direction. Results on other centers, possibly also related to interstitials, are discussed.
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