| In this paper, La/N-codoped SiC nanowires and La-doped SiC nanowires were prepared by different methods, the optimal preparation process was obtained through studying the field emission properties of as-prepared samples, and the products were systematieally characterized by different characterization methods. By Castep modules of Material studio software, the influence of different dopent on the energy band structure and density of states of SiC nanowires was studied. The main contents are as follows:(1) La/N-codoped SiC nanowires were synthesized by chemical vapor deposition and gas nitriding methods, based on the field emission properties of as-prepared samples, the optimal preparation process was: the reaction temperature was 800 ℃,and the heat preservation time was 180 min. The results proved that the nitrogen doping amount was 1.64%, lanthanum doping amount was 2.72%. The products prepared under the optimal preparation process maintained excellent field emission properties, the turn-on field and threshold field were 0.8 V·μm-1 and 2.6 V·μm-1,respectively.(2) La-doped SiC nanowires were synthesized by Two-steps method, the influence of lanthanum doping amount and heat preservation time was investigated,the optimal preparation process was: the amount of 0.01g·ml-1 LaCl3 was 1.5 ml, the heat preservation temperature was 1000 ℃, and the heat preservation time was 10 min.The products prepared under the optimal preparation process maintained excellent field emission properties, the turn-on field and threshold field were 1.7 V·μm-1 and 3.2V·μm-1, respectively.(3) The first-principles calculations were used to study the influence of differentdopent on the energy band structure and density of states of SiC nanowires, and the results proved that the band gap of La/N-codoped SiC nanowires increased with the increase of the ratio of La dopent and N dopent, and the band gap of La-doped SiC nanowires decreased with the amount of La dopent. |
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