Papers by Keyword: Divacancy

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Authors: T.E.M. Staab, L.M. Torpo, M.J. Puska, Risto M. Nieminen
Authors: B.C. MacEvoy, K. Gill, G. Hall
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: Adam Gali, M. Bockstedte, Nguyen Tien Son, T. Umeda, Junichi Isoya, Erik Janzén
Abstract: Only recently the well-resolved hyperfine structure of the P6/P7 EPR center has been experimentally observed. Based on the calculated hyperfine tensors we assign the P6/P7 center to the high spin state neutral divacancy, which is the ground state in agreement with the experiment. We propose a mechanism to explain the loss of divacancy signal at high tem- perature annealing in semi-insulating SiC samples. We discuss the possible correlation between the divacancy and some photoluminescence centers.
Authors: G.N. Kamaev, M.D. Efremov, V.A. Stuchinsky, B.I. Mihailov, S.G. Kurkin
Abstract: In present work temperature stable conductivity is considered for neutron-doped FZ silicon with point radiation defects. It was shown that divacancy formed after electron irradiation allow to increase resistivity of silicon at room temperature, what lead to less variation of conductivity in a range of temperatures 20-160C. Discrepancy between experimental and theoretical data was evaluated and corrected with introduction in the model deep level center Ec-0.6eV. As result of investigation power resistors were elaborated with 10% deviation from nominal value within the range of temperatures.
Authors: W. Qiu, F.X. Gan, Li Gang Yao, Sven Odendahl
Authors: Nguyen Tien Son, T. Umeda, Junichi Isoya, Adam Gali, M. Bockstedte, Björn Magnusson, Alexsandre Ellison, Norio Morishita, Takeshi Ohshima, Hisayoshi Itoh, Erik Janzén
Abstract: Electron paramagnetic resonance (EPR) studies of the P6/P7 centers in 4H- and 6H-SiC are reported. The obtained principal values of the hyperfine tensors of C and Si neighbors are in good agreement with the values of the neutral divacancy (VCVSi 0) calculated by ab initio supercell calculations. The results suggest that the P6/P7 centers, which were previously assigned to the photo-excited triplet states of the carbon vacancy-carbon antisite pairs in the double positive charge state (VCCSi 2+), are related to the triplet ground states of the C3v/C1h configurations of VCVSi 0.
Authors: Yasunori Tanaka, Naoto Kobayashi, Hajime Okumura, Ryoichi Suzuki, Toshiyuki Ohdaira, Mitsuru Hasegawa, M. Ogura, Sadafumi Yoshida, Hisao Tanoue
Authors: Viktor Ivády, Krisztián Szász, Abram L. Falk, Paul V. Klimov, Erik Janzén, Igor A. Abrikosov, David D. Awschalom, Ádám Gali
Abstract: Nowadays, computational techniques can greatly facilitate the identification of point defect related photoluminescence and EPR centers in semiconductors. Once the identification has been achieved, one can gain a detailed description of the microstructure and the electron configuration of the defect, providing a basis for further understanding and development. Recently, the importance of divacancy and related point defects in different polytypes of SiC has substantially increased due to their possible quantum bit application. However, their different configurations have not been satisfactorily identified yet. In our study, we carry out large-scale first principles supercell calculations to identify the divacancy related point defects in 4H and 6H-SiC. By resolving some general accuracy issues of usual ab initio supercell techniques, we are able to obtain convergent photoluminescence (PL) energies, zero-field-splitting, and hyperfine parameters. Our results confirm the previous assignment of the PL1-4 PL lines in 4H-SiC (also known as UD-2 luminescence lines previously) to the four possible divacancy configurations and provide the identification of QL1,QL2, and QL6 PL lines in 6H-SiC. In all cases the calculated zero-field and hyperfine tensors’ parameters are provided.
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