| 研究実績の概要 |
The aim of this study is to perform fundamental and applied studies on porous nano-silicon, nano-silicon oxide, plasmonic nano-metal-silicon composite layers, and powders, for the control of nano-structure shape, size and surface chemistry, luminescence (emission spectrum, lifetime, efficiency and stability) and electrical conductivity. These materials will be applied to multi-color lighting, sensing, and photovoltaics.
The knowledge acquired in the previous year has been used in the next step: the study of the photoetching of porous Si (PSi) in HF in a view to (i) understand and characterize the photoetching effect and (ii) assess its potential for size control. Two regimes were characterized, one in which the photoetch rate is limited by the supply of photo-generated holes, and another one where it is limited by the photoetching reaction. The maximum photoetch rate was derived. A model was developed to understand photoetching. This work will be presented as invited talk in Fall 2018 ECS conference.
The photo-oxidation of PSi has been attempted. Its kinetics was found very slow and probably unusable for practical purposes. The results still represent some fundamental interests and will be continued, time permitting.
In parallel, very high and stable absolute visible luminescence quantum yield was achieved using powders of Si nanocrystals oxidized under high-pressure.
A new method of chemical modification of nano-silicon surface to replace Si-H bonds by more stable Si-C bonds has been shown. It is efficient and the resulting PSi layers are stabilized.
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