[19a-221A-1~10] 9.2 Nanowires and Nanoparticles

▲ [19a-221A-5] Stable Luminescent Silicon Nanocrystals and Porous Silicon Powders with Very High Quantum Yield Passivated by High-pressure Water Vapor Annealing

〇Bernard Gelloz¹, Firman Bagja Juangsa², Tomohiro Nozaki², Nobuyoshi Koshida³, Lianhua Jin⁴ (1.Nagoya Univ., 2.Tokyo Inst. Tech., 3.Tokyo Univ. Agr.&Tech., 4.Yamanashi Univ.)

Keywords:silicon, luminescence, quantum yield

Silicon nanocrystals (SiNCs) have been fabricated using a high-frequency non-thermal plasma reactor. The as-prepared SiNCs were mostly spherical, hydrogen-terminated, and exhibited an average size of about 6 nm. In order to get visible luminescence from these SiNCs, their size had to be decreased. We have used a low-temperature oxidation technique that has been shown to provide high-efficiency and very stable luminescent porous silicon layers: high-pressure water vapor annealing (HWA). A thin oxide layer of about 1 nm was formed at the surface of the SiNCs. Various luminescence properties of the treated SiNCs will be presented. The most striking results are (i) high stability, (ii) very high absolute quantum yields (~ 55% for the SiNCs powder; ~30% for porous silicon powders), and (iii) the longest luminescence lifetimes reported to date (e.g. ~ 250 µs at 825 nm).