title: Growth and characterization of well-aligned densely-packed rutile TiO(2) nanocrystals on sapphire substrates via metal-organic chemical vapor deposition.
abstract: Well-aligned densely-packed rutile TiO(2) nanocrystals (NCs) have been grown on sapphire (SA) (100) and (012) substrates via metal-organic chemical vapor deposition (MOCVD), using titanium-tetraisopropoxide (TTIP, Ti(OC(3)H(7))(4)) as a source reagent. The surface morphology as well as structural and spectroscopic properties of the as-deposited NCs were characterized using field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), selected-area electron diffractometry (SAED), x-ray diffraction (XRD) and micro-Raman spectroscopy. FESEM micrographs reveal that vertically aligned NCs were grown on SA(100), whereas the NCs on the SA(012) were grown with a tilt angle of ∼33° from the normal to substrates. TEM and SAED measurements showed that the TiO(2) NCs on SA(100) with square cross section have their long axis directed along the [001] direction. The XRD results reveal TiO(2) NCs with either (002) orientation on SA(100) substrate or (101) orientation on SA(012) substrate. A strong substrate effect on the alignment of the growth of TiO(2) NCs has been demonstrated and the probable mechanism for the formation of these NCs has been discussed.
authors.affiliation: Department of Electronic Engineering, National Taiwan University of Science and Technology, Taipei 106, Taiwan.
authors.forename: C A
authors.initials: CA
authors.lastname: Chen
authors.forename: Y M
authors.initials: YM
authors.lastname: Chen
authors.forename: A
authors.initials: A
authors.lastname: Korotcov
authors.forename: Y S
authors.initials: YS
authors.lastname: Huang
authors.forename: D S
authors.initials: DS
authors.lastname: Tsai
authors.forename: K K
authors.initials: KK
authors.lastname: Tiong