Electronic Transport in NbSe₂ Two-Dimensional Nanostructures: Semiconducting Characteristics, Surface passivation and Photoconductivity
M. D. Xiao(蕭名登)1, Y. H. Huang(黃怡華)1, R.S. Chen(陳瑞山)1*, J.R Zhang(張家榮)3, Y.S. Huang(黃鶯聲)2
1Graduate Institute of Applied Science and Technology, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
2Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
3Graduate Institute of Electro-optical Engineering, National Taiwan University of Science and Technology, Taipei 10607, Taiwan
* presenting author:蕭名登, email:tzcoba01@gmail.com
The electronic transport properties of two-dimensional (2D) niobium diselenide (NbSe2) layer materials with two-hexagonal single-crystalline structures grown by chemical vapor transport have been investigated. Those NbSe2 nanostructures isolated simply using mechanical exfoliation have been found to exhibit lower conductivity and semiconducting properties, compared with their bulk metallic counterparts. The presence of electron trap states at the surface was proposed as an explanation for the reduced dark conductivity in the 2D NbSe2 nanostructures. The surface states can be passivated by surface coating using the organic material of bathocuproine (BCP). After passivation, the NbSe2 nanoflakes recover to metallic state and the conductivities were high enhanced. In addition, the pristine NbSe2 nanoflakes exhibit a remarkable photoresponse under different wavelength and intensity excitations. The photocurrent responsivity and photoconductive gain can reach 3.8 AW-1 and 300, respectively; these values are higher than those of graphene and MoS2 monolayers and comparable with those of GaS and GaSe nanosheets.


Keywords: Niobium Diselenide, layer material, nanostructure , transport property, photoconductivity