Abstract:

The electronic structure and optical properties of CrSi₂ with vacancy defect were calculated based on the first principles method, and the photoelectric properties of CrSi₂ with Cr or Si vacancy defect were analyzed. The results show that the lattice constants and volume are all decreased with Cr or Si vacancy defect. The band structure becomes intensive and gentle, and moves upward. The band structure of CrSi₂ with Si vacancy defect is p type indirect semiconductor with a band gap of 0.35 eV; while two new energy levels are induced in the forbidden band with Crvacancy defect. Density of states of
 the valence band top and conduction band bottom are mainly composed of Cr 3d. Sivacancy defect has a little effect on the density of states; Crvacancy defect improves the density of states of the Fermi energy. Compared with that of pure CrSi₂, the dielectric peak slightly moves to the lower energy and decreases with vacancy defect, and the absorption index obviously decreases.

Key words: CrSi₂； vacancy defect； photoelectric properties； , the first principle