토토 세븐PHYSICS/BK21 SEMINAR[09.11.25]

                                                               
“Functionalization and Chemical
Properties of Graphene”
  
Ø ♦ Speaker :토토 세븐Prof. Sunmin Ryu [Kyung Hee University]
Ø ♦ Place : Physics Seminar Room (Science Bldg, 3-201)
Ø ♦ Date & Time : Nov, 25(Wed)토토 세븐3:00토토 세븐~토토 세븐4:00 pm

Abstract
  
Atom-thick graphene membrane holds substantial potential for applications in future molecular-scale
integrated electronics, transparent토토 세븐conducting토토 세븐membranes,토토 세븐nanocomposites,토토 세븐etc.토토 세븐To토토 세븐realize토토 세븐this
potential, chemical properties of graphene need to be understood and토토 세븐functionalization토토 세븐toolkits토토 세븐are
also required. To meet this need,토토 세븐surface토토 세븐chemistry토토 세븐of토토 세븐graphene토토 세븐has토토 세븐been토토 세븐explored토토 세븐by토토 세븐Raman
spectroscopy, AFM and STM scanning probes. In the first part of the talk, two chemical reactions of
graphene will be presented.토토 세븐Hydrogenation,토토 세븐the토토 세븐simplest토토 세븐basal토토 세븐plane토토 세븐functionalization,토토 세븐is토토 세븐highly
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 higher토토 세븐rate
for single layer than double layer토토 세븐graphene 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-doping토토 세븐in토토 세븐supported토토 세븐graphene토토 세븐is토토 세븐mediated by oxide
substrates. An STM study토토 세븐reveals토토 세븐that토토 세븐thermal토토 세븐annealing토토 세븐generates토토 세븐out-of-plane토토 세븐deformation토토 세븐of
nanometer-scale wavelength and distortion in sp2 bonding on an atomic scale. Graphene토토 세븐deformed
by annealing is found to be chemically active enough to토토 세븐bind토토 세븐molecular oxygen,토토 세븐which토토 세븐leads t o토토 세븐a
strong hole-doping. A possible form of oxides will be discussed.
  
  
Contact Person : Prof. Nam Ki Lee (054-279-2097,nklee@postech.ac.kr)