Transport Properties in semiconducting NbS2 and NbSe2 Nanoflakes
Yi-Hua Huang1*, Ruei-San Chen1, Chih-cheng Peng2, Jia-Rong Zhang3, Ying-Sheng Huang2
1Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, Taiwan
2Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, Taiwan
3Graduate Institute of Electro-optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan, Taiwan
* presenting author:黃怡華, email:evajoanna@hotmail.com
The electronic transport properties of the 3R-niobium disulfide (NbS2) and 2H-niobium diselenide (NbSe2) nanoflakes mechanically exfoliated from the bulk crystal grown by chemical vapor transport (CVT) were investigated. It is found that the conductivity values of the single-crystalline NbS2 nanoflakes are approximately two order of magnitude lower than that of their bulk counterparts. Similar result was also observed in the NbSe2 system. Temperature-dependent conductivity measurements show that the 3R-NbS2 and 2H-NbSe2 nanoflakes exhibit semiconducting transport behavior, which is different from the metallic nature in their bulk crystal. The very shallow activation energies is at 1-4 meV and 12-19 meV for the NbS2 and NbSe2 nanoflakes, respectively. In addition, the photocurrent response were also observed. The probable mechanism resulting in the different transport behaviors between the nanostructure and bulk for NbS2 and NbSe2 were also discussed.


Keywords: niobium disulphide, niobium diselenide, conductivity, activation energy