Vanadium-related Center in 4H Silicon Carbide

Theoretical unification of hybrid-DFT andDFT + Umethods for the treatment of localized orbitals

“…According to Magnusson et.al. 83,84 , the ground state of the defect is located 2.1 ± 0.1 eV below the conduction band edge and there is an inter impurity transition (e → e) with 0.97 eV energy in the case of V Si defect at h site. With the HSE06 functional one can predict 2.76 eV and 2.369 eV for the position of the highest occupied orbital and for the excitation energy.…”

“…The motivation for this comparison is that the nonempirical optimally tuned hybrids can reproduce excitation energies and quasiparticle spectra [27,28] and furthermore we could successfully correlate the KS eigenvalues of HSE06 + V w calculation with quasiparticle energies [53]. According to Magnusson et al [81,82], the ground state of the defect is located 2.1 ± 0.1 eV below the conduction band edge and there is an interimpurity transition (e → e) with 0.97 eV energy in The more careful treatment of the charge correction compared to our previous study reduces the refined w parameter value with 0.5 eV. Therefore, the calculated positive neutral charge transition level (+|0) is slightly shifted downward with 0.06 eV.…”

Role of Fermi-level depinning in quenching of V4+ related photoluminescence in semi-insulating 4H-SiC

“…In PL experiments, two sets of vanadium-related intra-band transitions (α lines and β lines) are commonly observed depending on the substitution site (hexagonal or cubic) in 4H-SiC. Typically, the low temperature PL spectra obtained for V 4+ in 4H-SiC consists of a doublet β 1,2 (928.4 meV) attributed to substitution at the hexagonal site while the other four lines α 1 (967.3 meV), α 2 (968.1 meV), α 3 (969.5meV), and α 4 (970.3 meV) are assigned to originate from the cubic site [7,[28][29][30][31]. The exact site assignments of these transitions are still under debate.…”