Premium
Hierarchical Structure of TiO 2 Nano‐Aggregates Prepared by Pulsed Laser Ablation in Background Gas
Author(s) -
UMEZU IKUROU,
YOSHIDA TAKEHITO
Publication year - 2016
Publication title -
electronics and communications in japan
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.131
H-Index - 13
eISSN - 1942-9541
pISSN - 1942-9533
DOI - 10.1002/ecj.11871
Subject(s) - anatase , materials science , substrate (aquarium) , nanoparticle , scanning electron microscope , porosity , laser ablation , rutile , titanium dioxide , nanotechnology , nanostructure , laser ablation synthesis in solution , nano , laser , plume , chemical engineering , pulsed laser deposition , thin film , composite material , laser power scaling , optics , chemistry , photocatalysis , biochemistry , oceanography , physics , engineering , x ray laser , thermodynamics , geology , catalysis
SUMMARY We prepared titanium dioxide (TiO 2 ) nanoparticles by pulsed laser ablation of TiO 2 target in O 2 background gas. Effects of background gas pressure and substrate target distance on the structure of deposited films are clarified. The primary structure, nanocrystals, changes from rutile to anatase phase with increasing background gas pressure or substrate target distance. The porosity of aggregated structure increases with increasing background gas pressure or substrate target distance. These results indicate that confinement of the plume between target and substrate is important for structural formation. The hierarchical micron‐ and submicron‐sized structures were found by the analysis of scanning electron microscope images. The deposits are composed of primary, secondary, and tertiary structures: They are nanoparticles, submicron‐sized aggregates, and micron‐sized aggregates. The nonequilibrium aggregation processes of nanoparticles in the plume and/or on the substrate are essential for the formation of hierarchical structure.