講演情報
[15a-K307-5]Nature of the Enhancement of Luminescence Efficiency by High-Pressure Water Vapor Annealing in Si Single Nanocrystals
〇Bernard Gelloz1, Xi Lu2, Jingjian Zhou3, Ilya Sychugov2 (1.Nagoya Univ., 2.KTH Royal Inst. Tech., 3.Uppsala Univ.)
キーワード：
silicon、nanocrystal、luminescence
High-pressure water vapor annealing (HWA) improves the photoluminescence (PL) efficiency of Si nanostructures and powders of Si/SiO2 core/shell nanocrystals (NCs). Such ensembles of NCs consist of dark (non-emissive), grey (not 100% efficient) and bright (100% efficient) NCs. HWA grows surface oxide or increases the thickness of an already existent oxide. The enhancement in luminescence efficiency by HWA was attributed to reduced stress and defect density in the oxide shells. It could also be related to some change in the population of “dark”, “grey” and “bright” NCs. To study which of the three types of NCs are mostly affected by HWA and how, we have studied single Si NCs. The average blinking duty cycle of Si NCs was enhanced without changing the average ON-state PL intensity, indicating reduced carrier trapping on the Si/SiO2 interfaces and confirming the decrease in interface defects. HWA was also found to brighten “grey” NCs, rather than changing “dark” NCs to “bright” NCs.