Identification of Niobium in 4H-SiC by EPR and ab Initio Studies
2012 (English)In: Materials Science Forum Vols 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, 217-220 p.Conference paper (Refereed)
In unintentionally Nb-doped 4H-SiC grown by high-temperature chemical vapor deposition (HTCVD), an electron paramagnetic resonance (EPR) center with C-lh symmetry and an electron spin S=1/2 was observed. The spectrum shows a hyperfine structure consisting of ten equal-intensity hyperfine (hf) lines which is identified as due to the hf interaction between the electron spin and the nuclear spin of Nb-93. An additional hf structure due to the interaction with two equivalent Si neighbors was also observed. Ab initio supercell calculations of Nb in 4H-SiC suggest that Nb may form a complex with a C-vacancy (V-C) resulting in an asymmetric split-vacancy (ASV) defect, Nb-Si-V-C. Combining results from EPR and supercell calculations, we assign the observed Nb-related EPR center to the hexagonal-hexagonal configuration of the AVS defect in the neutral charge state, (Nb-Si-V-C)(0).
Place, publisher, year, edition, pages
Trans Tech Publications Inc., 2012. Vol. 717-720, 217-220 p.
Transition metal impurity; split-vacancy defect; electron paramagnetic resonance; ab initio calculations
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-87571DOI: 10.4028/www.scientific.net/MSF.717-720.217ISI: 000309431000050OAI: oai:DiVA.org:liu-87571DiVA: diva2:589563
14th International Conference on Silicon Carbide and Related Materials (ICSCRM 2011), 11-16 September 2011, Cleveland, OH, USA