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RRJOMS | Volume 5 | Issue 4 | July, 2017
July 27-29, 2017 Vancouver, Canada
10
th
International Conference on
Emerging Materials and Nanotechnology
Growth, structural and electrical properties of VO
2
/ZnO nanostructures
Sang-Wook Han, In-Hui Hwang, Zhenlan Jin
and
Chang-In Park
Jeonbuk National University, Korea
V
O
2
is a typical metal-insulator-transition (MIT) material with the bandgap of ~0.7 eV and the Tc of ~ 70
o
C. VO
2
is
transparent and dark below and above the Tc, so that it can be applicable for smart windows by controlling the temperature.
VO
2
nanoparticles in a metallic phase block and scatter sunlight. The scattered sunlight by VO
2
nanoparticles can be used in
solar cells. We examined the local structural and electrical properties fromVO
2
/ZnO nanostructures by using the simultaneous
measurements of X-ray absorption fine structure (XAFS) and resistance. The structural and electrical properties of VO
2
depend
on the length of ZnO nanorods underneath VO
2
. Direct comparison of simultaneously-measured resistance and XAFS from
the VO
2
demonstrates that the transitions of structures, local density of the V 3d orbital states, and resistance occurred in
sequence during heating, whereas the properties changed simultaneously during cooling. XAFS reveals a substantial increase
of Debye-Waller factors, particularly, V-V pairs along the {111} direction in the metallic phase. XAFS results indicate that
soft phonon above Tc plays a critical role in the collapse of a small band gap of VO
2
. The local structural and the electrical
properties of VO
2
/ZnO nanorods are considerably sensitive to the interface of VO
2
/ZnO as well as the length of ZnO nanorods.
The interface properties of VO
2
hetero-structures should be considered for its applications to smart windows and solar cells.
Biography
Sang-Wook Han has published over 70 research papers in Solid State Physics, Nanoscience, and Nanotechnology and given over 30 invited lectures. His major
research field is the micro-structural and chemical property characterizations of nanomaterials using X-ray absorption fine structure (XAFS) and nanomaterial
applications including sensors, battery, and solar cells.
shan@jbnu.ac.krSang-Wook Han et al., Res. Rev. J Mat. Sci. 2017
DOI: 10.4172/2321-6212-C1-002