올림픽 토토PHYSICS/BK21 SEMINAR[09.11.25]

                                                               
“Functionalization and Chemical
Properties of Graphene”
  
Ø ♦ Speaker :올림픽 토토Prof. Sunmin Ryu [Kyung Hee University]
Ø ♦ Place : Physics Seminar Room (Science Bldg, 3-201)
Ø ♦ Date & Time : Nov, 25(Wed)올림픽 토토3:00올림픽 토토~올림픽 토토4:00 pm

Abstract
  
Atom-thick graphene membrane holds substantial potential for applications in future molecular-scale
integrated electronics, transparent올림픽 토토conducting올림픽 토토membranes,올림픽 토토nanocomposites,올림픽 토토etc.올림픽 토토To올림픽 토토realize올림픽 토토this
potential, chemical properties of graphene need to be understood and올림픽 토토functionalization올림픽 토토toolkits올림픽 토토are
also required. To meet this need,올림픽 토토surface올림픽 토토chemistry올림픽 토토of올림픽 토토graphene올림픽 토토has올림픽 토토been올림픽 토토explored올림픽 토토by올림픽 토토Raman
spectroscopy, AFM and STM scanning probes. In the first part of the talk, two chemical reactions of
graphene will be presented.올림픽 토토Hydrogenation,올림픽 토토the올림픽 토토simplest올림픽 토토basal올림픽 토토plane올림픽 토토functionalization,올림픽 토토is올림픽 토토highly
reversible and strongly dependent on the thickness of graphene in the rate. Graphene sheets can be
locally hydrogenated with a high spatial resolution. Thermal oxidation also proceeds at a higher올림픽 토토rate
for single layer than double layer올림픽 토토graphene and triple layer graphene behaves like bulk graphite. The
second part of the talk will illustrate the influence of underlying silicon dioxide substrates and ambient
gases on properties of graphene. Raman spectroscopy shows that freestanding graphene is essentially
charge-neutral implying that the “usual” hole-doping올림픽 토토in올림픽 토토supported올림픽 토토graphene올림픽 토토is올림픽 토토mediated by oxide
substrates. An STM study올림픽 토토reveals올림픽 토토that올림픽 토토thermal올림픽 토토annealing올림픽 토토generates올림픽 토토out-of-plane올림픽 토토deformation올림픽 토토of
nanometer-scale wavelength and distortion in sp2 bonding on an atomic scale. Graphene올림픽 토토deformed
by annealing is found to be chemically active enough to올림픽 토토bind올림픽 토토molecular oxygen,올림픽 토토which올림픽 토토leads t o올림픽 토토a
strong hole-doping. A possible form of oxides will be discussed.
  
  
Contact Person : Prof. Nam Ki Lee (054-279-2097,nklee@postech.ac.kr)