The temperature dependence of the direct gap of β-FeSi2 films

Indirect optical absorption of single crystalline β-FeSi2

“…A number of experimental studies on the band gap nature of β-FeSi 2 have been performed by optical absorption measurements. From the analysis of the energy dependence of the absorption coefficient, in most reports it is argued that β-FeSi 2 has a direct band gap [1,2,6,7,8,9,10,11,12], but a few papers report an indirect gap lower than the direct one by some tens of meV. [13,14,15].…”

Synthesis and characterization of β-phase iron silicide nano-particles by chemical reduction

“…Although most of the optical experimental observation conducted by Bost et al [48] and other authors [1,[49][50][51][52] showed that ␤-FeSi 2 is a direct band gap semiconductor with E g = 0.85-0.87 eV the papers related to band structure calculated by several authors [1,6,7,31,32] showed that it is both direct band gap semiconductor at Y and point as well as indirect band gap semiconductor along to Y along high symmetry directions. According to Filonov et al [1] and Eisebitt et al [34] the most important feature of the band structure is characterized by a direct band gap at point lies in between and Z k points which is 0.742 eV and 0.78 eV, respectively, whereas according to Christensen et al [32] and Eppenga et al [31] the calculated direct gap value at is about 0.80 eV and 0.92 eV, respectively.…”

“…On the other hand, some of the authors [37,50] have shown experimentally that ␤-FeSi 2 is a direct band gap as well as indirect band gap semiconductor whereas indirect energy gap is a few meV lower than the direct band gap. As discussed earlier Bost and Mahan [48] have also shown that it is a direct band gap semiconductor with a band gap of 0.87 eV.…”