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Indexed by:期刊论文

Date of Publication:2018-04-01

Journal:CHINESE PHYSICS B

Included Journals:SCIE

Volume:27

Issue:4

ISSN No.:1674-1056

Key Words:4H-SiC; interface defect; density of states; first principle

Abstract:An amorphous SiO2/4H-SiC (0001) interface model with carbon dimer defects is established based on density functional theory of the first-principle plane wave pseudopotential method. The structures of carbon dimer defects after passivation by H-2 and NO molecules are established, and the interface states before and after passivation are calculated by the Heyd-Scuseria-Ernzerhof (HSE06) hybrid functional scheme. Calculation results indicate that H-2 can be adsorbed on the O-2-C = C-O-2 defect and the carbon-carbon double bond is converted into a single bond. However, H-2 cannot be adsorbed on the O-2-(C = C)'-O-2 defect. The NO molecules can be bonded by N and C atoms to transform the carbon-carbon double bonds, thereby passivating the two defects. This study shows that the mechanism for the passivation of SiO2/4H-SiC (0001) interface carbon dimer defects is to convert the carbon-carbon double bonds into carbon dimers. Moreover, some intermediate structures that can be introduced into the interface state in the band gap should be avoided.