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Enhancement of the emission from TeO 2 nanorods by encapsulation with ZnO
Author(s) -
Jin Changhyun,
Kim Hyunsu,
Lee Chongmu
Publication year - 2011
Publication title -
crystal research and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.377
H-Index - 64
eISSN - 1521-4079
pISSN - 0232-1300
DOI - 10.1002/crat.201100224
Subject(s) - nanorod , photoluminescence , materials science , transmission electron microscopy , crystallite , amorphous solid , tetragonal crystal system , scanning electron microscope , nanotechnology , atomic layer deposition , luminescence , optoelectronics , layer (electronics) , chemical engineering , crystallography , composite material , crystal structure , chemistry , metallurgy , engineering
TeO 2 ‐core/ZnO‐shell nanorods were synthesized by a two–step process comprising thermal evaporation of Te powders and atomic layer deposition of ZnO. Scanning electron microscopy images exhibit that the core‐shell nanorods are 50 ‐ 150 nm in diameter and up to a few tens of micrometers in length, respectively. Transmission electron microscopy and X‐ray diffraction analysis revealed that the cores and shells of the core‐shell nanorods were polycrystalline simple tetragonal TeO 2 and amorphous ZnO with ZnO nanocrystallites locally, respectively. Photoluminescence measurement revealed that the TeO 2 nanorods had a weak broad violet band at approximately 430 nm. The emission band was shifted to a yellowish green region (∼540 nm) by encapsulation of the nanorods with a ZnO thin film and the yellowish green emission from the TeO 2 ‐core/ZnO‐shell nanorods was enhanced significantly in intensity by increasing the shell layer thickness. The highest emission was obtained for 125 ALD cycles (ZnO coating layer thickness: ∼15 nm) and its intensity was much higher than that of the emission from the uncapsulated TeO 2 nanorods. The origin of the enhancement of the emission by the encapsulation is discussed in detail. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)