a1 Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong, Hong Kong, People's Republic of China
Nanocrystalline tin dioxide (SnO2) thin films were prepared on glass substrate by pulse laser deposition for the first time. The thin films were characterized for their composition, morphology, and crystalline structure by x-ray diffraction, transmission electron microscopy, and high-resolution transmission electron microscopy. It was found that the thin films consisted only of the tetragonal phase SnO2 with no structural change, and they were well crystallized during deposition. In most cases, SnO2 particles were overlapped, predominantly grown on preferred (101) plane, and connected with two or three neighbors through necks. The average grain size of the as-prepared thin films was about 12 nm. These facts are of great importance for sensor characteristics, since smaller grains and preferred orientation properties provide higher gas sensitivity to the whole thin films. Our findings indicate that the n-type wide-band-gas semiconductor nanocrystalline thin films can be manipulated by using pulse laser deposition techniques, offering new opportunities to control material fabrication.
(Received January 20 2003)
(Accepted February 26 2003)
p1 Present address: Department of Physics and Materials Science, on leave from the Structure Research Laboratory, University of Science and Technology of China, Hefei 230026, Anhui, People's Republic of China. e-mail: email@example.com