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článek v časopise v databázi Web of Science
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Despite being technologically very attractive, highly-doped zinc oxide whiskers with precisely defined
morphology and doping level are difficult to prepare. Here, as an advancing step towards this goal, we show that pre-annealing of ZnO in oxygen-poor conditions (e.g. high vacuum) at low temperature encourages a deeper diffusion of Ga into the ZnO crystal lattice in contrast to ZnO pre-annealed in oxygen-rich conditions. We also demonstrate that gallium acts as a reactant causing ZnO etching at diffusion temperatures, contrary to Al-based doping of ZnO systems. This behaviour, being similar to gallium melt-back etching during GaN epitaxy on silicon, has not been observed for ZnO so far and can represent a significant hurdle for the post-growth diffusion doping of ZnO nanostructures. The paper suggests possible ways how to diminish this effect.
morphology and doping level are difficult to prepare. Here, as an advancing step towards this goal, we show that pre-annealing of ZnO in oxygen-poor conditions (e.g. high vacuum) at low temperature encourages a deeper diffusion of Ga into the ZnO crystal lattice in contrast to ZnO pre-annealed in oxygen-rich conditions. We also demonstrate that gallium acts as a reactant causing ZnO etching at diffusion temperatures, contrary to Al-based doping of ZnO systems. This behaviour, being similar to gallium melt-back etching during GaN epitaxy on silicon, has not been observed for ZnO so far and can represent a significant hurdle for the post-growth diffusion doping of ZnO nanostructures. The paper suggests possible ways how to diminish this effect.
