Acta Phys. -Chim. Sin. ›› 2015, Vol. 31 ›› Issue (6): 1191-1198.doi: 10.3866/PKU.WHXB201504011

• PHYSICAL CHEMISTRY OF MATERIALS • Previous Articles     Next Articles

Preparation, Field Emission Characteristics and First-Principles Calculations of La-Doped or N-Doped SiC Nanowires

LI Zhen-Jiang1, MA Feng-Lin1, ZHANG Meng1, SONG Guan-Ying1, MENG A-Lan2   

  1. 1 Key Laboratory of Polymer Material Advanced Manufactorings Technology of Shandong Provincial, College of Chinesisch- Deutsche Technische Fakultat, College of Electromechanical Engineering, Qingdao University of Science and Technology, Qingdao 266061, Shandong Province, P. R. China;
    2 State Key Laboratory Base of Eco-chemical Engineering, College of Chemistry and Molecular Engineering, Qingdao University of Science and Technology, Qingdao 266061, Shandong Province, P. R. China
  • Received:2014-12-15 Revised:2015-04-01 Published:2015-06-05
  • Contact: MENG A-Lan E-mail:alanmengqust@163.com
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (51272117, 51172115), Specialized Research Fund for the Doctoral Program of Higher Education of China (20123719110003), Tackling Key Program of Science and Technology in Shandong Province, China (2012GGX10218), and Application Foundation Research Program of Qingdao, China (13-1-4-117-jch).

Abstract:

La- and N-doped SiC nanowires were prepared using a vapor-phase doping method and chemical vapor deposition method, respectively. The morphologies, element analysis, and crystal structures of the products were characterized by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), selected area electron diffraction (SAED), high-resolution transmission electron microscope (HRTEM), X-ray energy dispersive spectrum (EDS), and X-ray diffraction (XRD). The field emission properties of the nanowires doped with different elements were tested by field emission measurements, and the results show that the turn on field (Eto) and threshold field (Ethr) of La-doped SiC nanowires are 1.2 and 5.2 V·μm-1, and those of N-doped SiC nanowires are 0.9 and 4.0 V·μm-1, respectively, these values are clearly lower than those of 2.3 and 6.6 V·μm-1 for undoped SiC nanowires. In addition, the density of states (DOS) and band structures of undoped, N-doped, and La-doped, SiC nanowires were also calculated using Castep of material studio on the basis of the first-principles. The results of the theoretical calculations suggest that the narrower gap may be attributed to the impurity energy level (La 5d or N 2p) generated near the Fermi level. Because of the narrower gap, electrons transfer from the valence band maximum (VBM) to conduction band minimum (CBM) need less energy, and this enhances the field emission property.

Key words: Field emission property, La-doping, N-doping, SiC nanowire, First-principles

MSC2000: 

  • O649