“Electron transport through weak-bonded
contact metal with low dimensional nanomaterial”
Dr. Ju-Jin Kim
Department of Physics, Jeonbuk National University
Nov. 1 (Fri.), 04:00 PM
E6-2. 1st fl. #1323
Abstract:
The electrical properties of low-dimensional nano-materials such as carbon nanotube, graphene,
layered materials can be effectively tuned by varying the Fermi level pinning position to the
metal electrode without conventional substitutional doping. By changing the work function of
metal electrode widely, we obtained the n-, p-, and ambi-polar type FETs with the same
conducting channel. In the case of mid-gap pinned transistors, the gate response presents ambipolar
type. By varying the global back-gate, we have modulated the band profile in the channel
from p-metal, through p-type semiconductor and n-type semiconductor, finally to n-metallic
state.
In the weak-bonded contact metal and nano-material with clean and inert surface, electrons
may tunnel through a well-defined Van-der-Waals (vdW) interface and charge transfer in
between them is very rare resulting in non-invasive density of states of the nano-materials near
the contact. This leads to develop a new type of tunneling spectroscopy method with vdW
interface: “a high resolution tunneling spectroscopy by adopting tunnel barrier as the vdW
interface metal and low-dimensional nano-structure without an artificial insulating tunnel
barrier”. The observed vdW tunneling spectra for carbon nanotube, graphene, layered materials
such as MoS2, 1T-TaS2, Bi-2212 will be presented.