Doping-induced effects on the band structure in n-type 3C-, 2H-, 4H-, 6H-SiC, and Si
1999 (English)In: Physical Review B. Condensed Matter and Materials Physics, ISSN 1098-0121, Vol. 60, no 24, 16479-16493 p.Article in journal (Refereed) Published
Doping-induced energy shifts of the lowest conduction band and the uppermost valence band have been calculated for n-type 3 C-, 2H-, 4H-, 6H-SiC, and Si. We present the resulting narrowing of the fundamental band gap and of the optical band gap as functions of donor concentration. The effects on the curvature of the lowest conduction band have been investigated in detail for 3C- and 6H-SiC and, moreover, the effective electron masses in the vicinity of the conduction-band minimum have been calculated for,all five materials. The calculations go beyond the common parabolic treatments of the ground-state energy dispersion by using energy dispersion and overlap integrals from band structure calculations. The nonparabolic valence-band curvatures especially strongly influence the self-energies, but also the double-well minimum of 6H-SiC has effects on the self-energies and the resulting band curvatures. By comparing the total energy of the electron gas with the total energy of electrons in a nonmetal phase, we estimate the critical Mott concentration for the metal-nonmetal transition. The utilized method is based on a zero-temperature formalism within the random phase approximation with local field correction according to Hubbard. [S0163-1829(99)12647-X].
Place, publisher, year, edition, pages
1999. Vol. 60, no 24, 16479-16493 p.
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-49894OAI: oai:DiVA.org:liu-49894DiVA: diva2:270790