Effect of in Doping on the ZnO Powders Morphology and Microstructure Evolution of ZnO:In Ceramics as a Material for Scintillators

Abstract

Transparent ZnO ceramics are of interest for use as material for high-efficiency fast scintillators. Doping ZnO ceramics in order to improve complex of their properties is a promising direction. In the present research, the role of indium in the ZnO nanopowders surface interactions and in the change of microstructures and photoluminescence (PL) characteristics of sintered cera-mics is considered. Undoped and 0.13 wt% In doped ZnO ceramics are obtained by hot pressing sintering. It has been found that indium leads to the transition of initially faceted ZnO particles to rounded, contributing to good sintering with formation of diffusion active grain boundaries (GBs). Unlike ZnO ceramics, ZnO:In ceramics microstructure is characterised by the trans-crystalline mode of fracture, faceted GBs with places of zig-zag forms and predominant distribution of In at the GBs. Such indium induced modifications of GBs promote removal of point defects and reduce PL parameter α = Idef/Iexc in comparison with the undoped ceramics. Results characterise ZnO:In cera-mics with improved GBs properties as a prospective material for scintillators.

ZnO and ZnO:Ga Ceramics for Advanced Scintillators

“…Moreover, there is a tendency to change the shape of some grains. True, not to the same extent, as under the influence of indium, however, this process is noticeable and according to known mechanisms of the sintering process, can be associated with the gallium influence on the grain growth stage [15,29,30]. The effect of gallium on the ceramics structure formation is confirmed by the SEM images of fracture mode results (Figure 2c, d).…”

Comparative Study on Micromechanical Properties of ZnO:Ga and ZnO:In Luminiscent Ceramics

“…1d, e) changing the shape of both grains and GBs: fine grains are irregular, elongated, some faceted grains have size of 8-12 µm, and a serrated shape of GBs appears. A similar influence of indium on the GBs shape in the ZnO ceramics based on different ZnO powders was described in [8]. Faceted straight GBs for the mechanical properties are the paths for the easy propagation of cracks.…”

“…Commercial zinc oxide powder (Sigma-Aldrich, USA) was used to obtain ceramics. The indium and gallium were introduced in the form of In 2 O 3 and Ga 2 O 3 by mechanical mixing with the original ZnO powder during 40 min at 293 K [8], [9]. The level of dopants was chosen based on previously studies [9] and corresponded to practically the same scintillation properties of In-and Ga-doped ZnO ceramics.…”

“…With the recent advances in hot press sintering technology, transparent ZnO ceramics based on nanopowders have aroused great interest for the use in fast and high-efficient photo-or X-ray luminescence scintillators [4]. Addition of donor dopants such as Ga or In leads to the improved scintillation characteristics of the ZnO ceramics [5]- [8]. However, the location of dopants in the microstructure is not yet clear.…”

“…However, the location of dopants in the microstructure is not yet clear. Moreover, despite many studies on the structural and optical properties of the doped ZnO:Ga and ZnO: In ceramics [8], [9], their mechanical characteristics remain practically unexplored even though the modern technology imposes rather strict requirements towards the mechanical properties of brittle optical components as they are subject to vibrations, small mechanical and thermal shock loads. The lack of comparative data on mechanical properties makes it difficult to use these ceramics.…”