A convenient fabrication technique for samarium hexaboride (SmB6) nanostructures (nanowires and nanopencils) is developed, combining magnetron-sputtering and chemical vapor deposition. Both nanostructures are proven to be single crystals with cubic structure, and they both grow along the direction. Formation of both nanostructures is attributed to the vapor-liquid-solid (VLS) mechanism, and the content of boron vapor is proposed to be the reason for their different morphologies at various evaporation distances. Field emission (FE) measurements show that the maximum current density of both the as-grown nanowires and nanopencils can be several hundred μA/cm2, and their FN plots deviate only slightly from a straight line. Moreover, we prefer the generalized Schottky-Nordheim (SN) model to comprehend the difference in FE properties between the nanowires and nanopencils. The results reveal that the nonlinearity of FN plots is attributable to the effect of image potential on the FE process, which is almost independent of the morphology of the nanostructures. All the research results suggest that the SmB6 nanostructures would have a more promising future in the FE area if their surface oxide layer was eliminated in advance.
Project supported by the National Key Basic Research Program of China (Grant No. 2013CB933601), National Project for the Development of Key Scientific Apparatus of China (Grant No. 2013YQ12034506), the Fundamental Research Funds for the Central Universities of China, the Science and Technology Department of Guangdong Province, China, the Education Department of Guangdong Province, China, and the Natural Science Foundation of Guangdong Province, China (Grant No. 2016A030313313).
- Xun Yang, Hai-Bo Gan, Yan Tian, Ning-Sheng Xu, Shao-Zhi Deng, Jun Chen, Huanjun Chen, Shi-Dong Liang, Fei Liu. An easy way to controllably synthesize one-dimensional SmB6 topological insulator nanostructures and exploration of their field emission applications[J]. Chin. Phys. B, 2017, 26(11): 118103.