Development of oxidation-free light-emitting material of silicon microparticles that have many fine trenches

2019 Fiscal Year Final Research Report

• Project/Area Number: 17H04962
• Research Category: Grant-in-Aid for Young Scientists (A)
• Allocation Type: Single-year Grants
• Research Field: Properties in chemical engineering process/Transfer operation/Unit operation
• Research Institution: Tokyo University of Agriculture and Technology
• Principal Investigator: Inasawa Susumu 東京農工大学, 工学(系)研究科(研究院), 准教授 (30466776)
• Project Period (FY): 2017-04-01 – 2020-03-31
• Keywords: シリコン / イガグリ形状 / 発光材料 / 表面酸化 / 発光輝度 / エッチング

Outline of Final Research Achievements

We examined development of silicon-based, durable light emitting particles that have unique trenched structures. Trenched silicon microparticles were obtained by chemical etching with a mixture of acids. They showed a visible orange-red emission from the trenched particles under excitation by ultra-violet (UV) light. We have revealed that oxidation under reduced pressure increased durability of the visible light emission from microparticles. Oxidation is a main cause that shortens the durability of light emission. But this result showed that oxidation would be a practical method to increase the durability if we use oxidation in a reasonable way. In addition, we have also examined etching process. Mixing of microparticles and the acid solution during etching was not preferable to proceed etching. Enough concentration of intermediate species around the microparticles is a key to produce trenched silicon microparticles.

Free Research Field

反応工学

Academic Significance and Societal Importance of the Research Achievements

本研究で対象としたシリコンマイクロ粒子は、特異なイガグリ形状である。この立体的な構造を活かし、大気中での酸化を防ぐシリコン発光材料の検討を行った。従来は酸化が消光の主原因であると捉えられていたが、本研究では減圧酸化を行うと発光輝度の低下が抑えられることを明らかにした。戦略的に酸化を用いれば、発光材料の長寿命化が可能であることを示唆する結果である。また、粒子エッチングで撹拌が逆効果であることを明らかにした。産業でも用いられるシリコンエッチングは、そのメカニズムに未解明の点が多い。イガグリ形状の制御にとどまらず、産業への貢献も可能な結果が得られた。