Abstracts Book - IMRC 2018

• SA6-O034
NANOSCALE INVESTIGATION OF ENHANCED FIELD ELECTRON
EMISSION FOR GOLD-DIAMOND NANOHYBRIDS
Sankaran Kamatchi Jothiramalingam 1,2 , Kalpataru Panda 3 , Balakrishnan Sundaravel 4 , I-Nan Lin 5 ,
Ken Haenen 1,2
1
Hasselt University, Institute for Materials Research, Belgium. 2 IMEC vzw, IMOMEC, Belgium.
3 KAIST, Center for Nanomaterials and Chemical Reactions, Korea. 4 Indira Gandhi Centre for
Atomic Research, Materials Physics Division, India. 5 Tamkang University, Department of
Physics, Taiwan.
Field emitters with superior field electron emission (FEE) characteristics are
employed as cold cathode materials in flat panel displays and other electron
emitting devices. Diamond possesses high FEE characteristics due to its negative
electron affinity, which makes it a promising material for applications as FEE
emitters. Recently, the main focus has been directed towards the synthesis of
the ultrananocrystalline diamond (UNCD) film, containing the ultra-small
diamond grains of 5–10 nm with smooth surface characteristics, which exhibits
higher electrical conductivity and better FEE properties than the other form of
diamond films. The sp 2 -bonded carbon in the grain boundaries of UNCD films is
conceived as the electron conduction channel in FEE. Moreover, the direct
detection of electron emission site the diamond grain or grain boundaries in
such a microscopic scale is crucial. Scanning tunneling microscopy (STM) is being
utilized to investigate the local FEE behavior and surface electronic properties of
diamond films.
In this work, a detailed STM investigation is carried out to locally image and
understand the mechanism behind enhanced conductivity and FEE properties
for Au-ion implanted UNCD films. The UNCD films, which were Au-ion implanted
with 1 x 10 17 ions/cm 2 , possess high electrical conductivity of 5076.0 S/cm and
low turn-on field of 1.6 V/μm with a high FEE current density of 5.4 mA/cm 2 (@
2.65 V/μm). Straight imaging of conducting/non-conducting sites is mapped by
STM. The local current-voltage measurements illustrate that grain boundaries
are the conducting/emitting sites. Further, this fact is supported by the high
resolution current imaging tunneling spectroscopy. The formation of abundant
conducting sp 2 nanographitic phases along the diamond grain boundaries,
confirmed transmission electron microscopic examinations, is believed to be the
genuine factor that helps for the easy transport of electrons and hence
enhances the conductivity/emission properties. The fabrication of these films