Transition Metal Defects in Cubic and Hexagonal Polytypes of SiC: Site Selection, Magnetic and Optical Properties from ab initio Calculations
2012 (English)In: Materials Science Forum Vol 717 - 720, Trans Tech Publications Inc., 2012, Vol. 717-720, 205-210 p.Conference paper (Refereed)
Relatively little is known about the transition metal defects in silicon carbide (SiC). In this study we applied highly convergent and sophisticated density functional theory (DFT) based methods to investigate important transition metal impurities including titanium (Ti), vanadium (V), niobium (Nb), chromium (Cr), molybdenum (Mo) and tungsten (W) in cubic 3C and hexagonal 4H and 6H polytypes of SiC. We found two classes among the considered transition metal impurities: Ti, V and Cr clearly prefer the Si-substituting configuration while W, Nb, and Mo may form a complex with a carbon vacancy in hexagonal SiC even under thermal equilibrium with similar concentration. If the metal impurity is implanted into SiC or when many carbon impurities exist during the growth of SiC then complex formation between the Si-substituting metal impurity and the carbon vacancy should be considered. This complex pair configuration exclusively prefers the hexagonal-hexagonal sites in hexagonal polytypes and may be absent in the cubic polytype. We also studied transition metal doped nano 3C-SiC crystals in order to check the effect of the crystal field on the d-orbitals of the metal impurity.
Place, publisher, year, edition, pages
Trans Tech Publications Inc., 2012. Vol. 717-720, 205-210 p.
point defects; hybrid density functional theory; transition metals; electron paramagnetic resonance; photoluminescence; site selection; polytypes
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-88453DOI: 10.4028/www.scientific.net/MSF.717-720.205ISI: 000309431000048OAI: oai:DiVA.org:liu-88453DiVA: diva2:604736
14th International Conference on Silicon Carbide and Related Materials (ICSCRM 2011), 11-16 September 2011, Cleveland, OH, USA