연사:  Dr. Chang-Yong Kim (Canadian Light Source)

일시: 2011년 10월 28일(금) 오전 11:00

장소:  물리학과 세미나실 (31355호실) 

초록: Grazing incidence X-ray diffraction and surface X-ray diffraction have been used to study mono-dispersive -Fe2O3 nano-cubes dip-coated on silicon wafer.
Hematite nanoparticle has drawn great research interest to overcome short decay length of charge carrier in solar energy conversion or to increase surface area for catalysis application.
Since chemical reaction or transport of charge carrier involve surface or interface of nanoparticle, study of surface atomic and electronic structure of nanoparticle is crucial. General consensus is that significant portion of atoms in a nanoparticle exhibits characteristic of surface/subsurface atom. Attempt to study the structural arrangement of surface/subsurface atoms of nanoparticle has been hampered due to an irregular/nonuniform shape and size of nanoparticle. Recent synthesis methods have progressed to produce mono-dispersive nanoparticles with a uniform shape. Provided proper alignment this type of nanoparticle could give opportunity to study surface structure of nanoparticle.
The -Fe2O3 nano-cubes enclosed by six identical {0 1 -1 2} planes have been synthesized with hydrothermal process. The synthesized nano-cubes with typical length scale of 50 nm were deposited on thermal oxide film of silicon wafer with a dip-coating method. Grazing incidence X-ray diffraction results revealed that the dip-coated nano-cubes were arranged by contacting the {0 1 -1 2} plane on the wafer. Preliminary surface X-ray scattering data were obtained from the dip-coated nano-cube surface. Thermal treatment effect to the nano-cube and possible application of monodispersive, uniform shape nanoparticle system will be discussed.
Figure 1. SEM (left) and grazing incidence X-ray diffraction (right) measurements from dip-coated -Fe2O3 nano-cubes.