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Nanoscale Microstructural and Chemical Analysis of SiO 2 –Zn 1− x Al x O Nanocomposites: Towards a Better Understanding of Si and Al Substitution in ZnO
Author(s) -
Gilbert Matthieu,
Byl Celine,
Berardan David,
Gloter Alexandre,
Dragoe Nita,
Vurpillot François
Publication year - 2015
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/jace.13848
Subject(s) - spark plasma sintering , materials science , nanoscopic scale , nanostructure , microstructure , nanocomposite , solubility , doping , grain boundary , chemical engineering , sintering , grain size , nanoparticle , matrix (chemical analysis) , nanotechnology , composite material , chemistry , optoelectronics , engineering
In this study, we report on the microstructure of SiO 2 ‐coated Al‐doped ZnO nanoparticles densified by spark plasma sintering(SPS), using a multiscale approach. Our observations show that it is possible to successfully prepare dense pellets while keeping the nanostructure with well‐defined Si‐rich grain boundaries. Although a very limited partial solubility of Si in the ZnO matrix has been observed, Si is mostly concentrated at the grain boundaries. More surprisingly, we evidenced some areas with nanoscale inhomogeneity of the Al concentration, which can locally strongly exceed the average composition of the matrix. It could explain the apparent discrepancy observed in the literature between the simultaneous presence of ZnAl 2 O 4 in Al‐doped ZnO, which should be the signature of the doping level exceeding the solubility limit, and the concentration of carriers that still depends on the nominal Al concentration in ZnO even in the presence of ZnAl 2 O 4 .