Surface termination that plays important roles in structural and physical properties of silicon nanocrystals - For a variety of device formations

2021 Fiscal Year Final Research Report

• Project/Area Number: 18K04242
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 21050:Electric and electronic materials-related
• Research Institution: University of Hyogo
• Principal Investigator: Sato Seiichi 兵庫県立大学, 理学研究科, 助教 (90326299)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: シリコンナノ粒子

Outline of Final Research Achievements

We studied crystal structures and physical properties of silicon nanoparticles after flash light irradiation or annealing. The surface silicon atoms of the nanoparticles were terminated with alkoxy and thiol groups, which are known as lattice-strain inducing and relaxing modifiers, respectively. By the flash light irradiation at room temperature, the diamond structured crystals were grown in both types of the nanoparticles, but a metastable structure was also found in the alkoxy terminated nanoparticles. By annealing the thiol terminated silicon nanoparticle films, narrow-gap porous silicon films with the bandgap energy of about 0.3 eV were obtained.

Free Research Field

コロイド科学

Academic Significance and Societal Importance of the Research Achievements

チオリンゴ酸修飾シリコンナノ粒子に窒素中250℃以上の熱処理を施すことで、それまで半導体的であったシリコンナノ粒子が金属的になることが明らかになった。このシリコンナノ粒子の導電性は雰囲気ガスの変化に大きく依存するため、新たな抵抗変化材料として期待できる。
また、シリコンナノ粒子・ゲルマニウムナノ粒子の混合膜に非平衡の結晶成長をさせたところ、正方晶ゲルマニウムと思われる結晶成長が確認された。これは、シリコン微結晶が結晶核となり、そこにゲルマニウム結晶が整合して成長することで形成されたものと考えられた。この現象は新構造ゲルマニウムの生成として興味深い。