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Gas‐Sensing Properties of Nanocrystalline WO 3 Films Made by Advanced Reactive Gas Deposition
Author(s) -
Solis Jose L.,
Hoel Anders,
Kish Laszlo B.,
Granqvist Claes G.,
Saukko Sami,
Lantto Vilho
Publication year - 2001
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2001.tb00868.x
Subject(s) - nanocrystalline material , monoclinic crystal system , materials science , tetragonal crystal system , grain size , scanning electron microscope , deposition (geology) , sintering , chemical engineering , analytical chemistry (journal) , crystal structure , mineralogy , nanotechnology , crystallography , composite material , chemistry , organic chemistry , paleontology , sediment , engineering , biology
Nanocrystalline WO 3 films were produced by advanced reactive gas deposition onto alumina substrates. The as‐deposited films had a tetragonal crystal structure and a mean grain size of around 6 nm, as found by X‐ray diffraction and electron microscopy. Sintering at a temperature τ s > 770 K yielded monoclinic films. We investigated the gas‐sensing properties of films sintered up to 870 K. After an initial “activation” at τ s = 750 K, the nanocrystalline WO 3 films showed excellent gas‐sensing properties, even at room temperature, on exposure to low concentrations of H 2 S in air. As little as 10 ppm of H 2 S made the conductance increase by a factor of about 10 3 within 10 min. The initial properties could be restored by heating the films to 530 K for 1 min.