Luminescent FeSi2/Si(111) Structures Induced by Heteroepitaxial Stress

The strained FeSi2 structures induced by heteroepitaxial stress on silicon crystal and the luminescent properties of the strained crystals have been investigated by using the first principles calculations. The heteroepitaxial β-FeSi2 crystals facing to Si(111) by (110) and (101) surfaces have been predicted to be deformed from the orthorhombic to the monoclinic crystals due to heteroepitaxial stress. For the FeSi2(110)/Si(111) and the FeSi2(101)/Si(111) relationship, we obtained distorted FeSi2 structures which have P21/c and C2/c space group symmetry, respectively. It was calculated that the P21/c structure has a direct type band structure and finite oscillator strength. So we consider that the monoclinic structure could be the origin of the light emission from the FeSi2/Si systems.