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Effect of micromorphology on transport properties of Nb‐doped anatase TiO 2 films: A transmission electron microscopy study
Author(s) -
Ogawa Daisuke,
Nakao Shoichiro,
Morikawa Kazuo,
Ebisawa Mizue,
Hirose Yasushi,
Hasegawa Tetsuya
Publication year - 2017
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201600606
Subject(s) - anatase , sputtering , amorphous solid , materials science , crystallite , transmission electron microscopy , doping , thin film , analytical chemistry (journal) , scanning electron microscope , sputter deposition , hall effect , mineralogy , nanotechnology , composite material , optoelectronics , electrical resistivity and conductivity , crystallography , chemistry , metallurgy , physics , photocatalysis , biochemistry , chromatography , quantum mechanics , catalysis
We investigate the transport properties and micromorphology of polycrystalline Nb‐doped anatase TiO 2 (TNO) transparent conductive films, as a function of working pressure ( p w ) during sputtering. The TNO films were crystallized from amorphous precursors sputter‐deposited on unheated glass substrates. The micromorphologies of the TNO films were observed using a transmission electron microscope. The film deposited at a high p w of 1 Pa showed an inhomogeneous micromorphology, and a substantially low Hall mobility ( μ H ) of 2.0 cm 2 V −1 s −1 . However, films deposited at a low p w of 0.75 and 0.5 Pa exhibited less inhomogeneity in the micromorphologies and a high μ H of 3.8 and 9.2 cm 2 V −1 s −1 , respectively. These results indicate that the inhomogeneous micromorphology acts as an additional carrier scattering source. The p w dependence of the micromorphology demonstrates that the inhomogeneous micromorphology originates from density fluctuation rather than sputter damage. The working pressure ( p w ) of sputtering significantly affects the micromorphology and, thus, the Hall mobility ( μ H ) of Nb‐doped anatase TiO 2 (TNO) transparent conductive thin films.