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Study of the Phase Transformation of Single Particles of Ga 2 O 3 by UV‐Raman Spectroscopy and High‐Resolution TEM
Author(s) -
Wang Xiang,
Xu Qian,
Fan Fengtao,
Wang Xiuli,
Li Mingrun,
Feng Zhaochi,
Li Can
Publication year - 2013
Publication title -
chemistry – an asian journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.18
H-Index - 106
eISSN - 1861-471X
pISSN - 1861-4728
DOI - 10.1002/asia.201300433
Subject(s) - nucleation , raman spectroscopy , particle (ecology) , materials science , high resolution transmission electron microscopy , phase (matter) , spectroscopy , crystallography , economies of agglomeration , particle size , transformation (genetics) , chemical physics , analytical chemistry (journal) , chemical engineering , nanotechnology , chemistry , transmission electron microscopy , optics , chromatography , biochemistry , physics , oceanography , organic chemistry , engineering , quantum mechanics , gene , geology
By taking advantage of UV‐Raman spectroscopy and high‐resolution TEM (HRTEM), combined with the focused ion beam (FIB) technique, the transformation from GaOOH into α‐Ga 2 O 3 and then into β‐Ga 2 O 3 was followed. We found that the stepwise transformations took place from the surface region before developing into the bulk of single particles without particle agglomeration and growth. During the transformation from GaOOH into α‐Ga 2 O 3 , the elimination of water vapor through the dehydroxylation of GaOOH resulted in the formation of micropores in the single particles, whilst maintaining their particle size. For the phase transformation from α‐Ga 2 O 3 into β‐Ga 2 O 3 , the nucleation of β‐Ga 2 O 3 was found to occur at the surface defects and this process could be retarded by occupying these defects with a small amount of La 2 O 3 . By finely controlling the process of the phase transformation, the β‐Ga 2 O 3 domains gradually developed from the surface into the bulk of the single particles without particle agglomeration. Therefore, the surface structure of the α‐Ga 2 O 3 single particles can be easily tuned and a particle with an α@β core–shell phase structure has been obtained.