| 研究実績の概要 |
The study of the photo-dissolution of porous silicon nanostructures was finalized. We confirmed that two regimes can take place, depending on the rate-limiting step of the reaction. The maximum photo-dissolution rate was derived. A model was developed. Simulations and fitting of experimental data was successful. This work was presented as an invited talk at the Fall 2018 ECS conference.
We have extended our study of the effect of oxidation under high pressure of silicon nanocrystals. We published very recently the results. We obtained Si/SiO2 core/shell nanoparticles with very high quantum yields (53-61%). The same method led to quantum yields of ~ 30% for porous silicon powders. These quantum yields are the highest obtained for Si/SiO2 core/shell nanoparticles. Moreover, our nanocrystals were very stable and exhibited the longest lifetimes ever reported for such nanocrystals.
Furthermore, a new method of chemical modification of nano-silicon surface to replace Si-H bonds by more stable Si-C bonds was studied. The originality of the method is to use gas-phase hydrosilylation with 1-hexene, which is liquid at room temperature and easy to manipulate without sophisticated vacuum devices. The effect of gas pressure was also studied. Our method is much more efficient than the liquid-phase one. The resulting photoluminescence of the nano-silicon layers was well-stabilized. The results were presented at JSAP Spring meeting 2019.
Finally, the study of the photo-oxidation of PSi has been expanded. The results are very interesting and the study is still under way.
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