Effects of reduced chemical vapor deposition environment on growth and optical characteristics of TiO2 nanobelts.
TiO2-delta nanobelts were self-catalytically grown at 510 degrees C on bare Si (100) substrates using metallorganic chemical vapor deposition. The nanobelt formation was critically affected by the partial pressure of oxygen. The nanobelts were grown when supplying only Ar or a mixed gas of Ar (90%) and H2 (10%), while thin films were formed with an O2 gas flow of more than 50 cm3 min(-1). The nanobelts consisted of approximately 20-30 nm size rutile-dominant nanocrystallites. A vapor-solid growth mechanism excluding a liquid phase appeared to control the nanobelt formation. The grown TiO2-delta nanobelts showed a strong photoluminescence (PL) spectra peak at approximately 550 nm due to oxygen vacancies. The nanobelt surface possessed significant amount of oxygen vacancies contributing PL and actively reacting with the environment, indicating promise for photocatalytic and gas sensor applications in a visible light regime.
Department of Materials Science and Engineering, Chungnam National University, Daejeon 305-764, Korea.
Nguyen Thi Quynh
NT
Hoa
Hun-Hoe
HH
Heo
Jae-Kyun
JK
Lim
Gil-Moo
GM
Kim
Eui-Tae
ET
Kim