Presentation Information
[23a-A305-2]Ultrahigh Porosity Photoluminescent Mesoporous Silicon with Greater than 50% Quantum Yields
〇Bernard Gelloz1, Leigh Canham2, Koji Asaka3, Yuto Nakamura1, Hideo Kishida1, Lianhua Jin4 (1.Nagoya Univ., 2.Birmingham Univ., 3.Fukui Univ. Tech., 4.Yamanashi Univ.)
Keywords:
silicon nanocrystal,photoluminescence,silicon nanostructure
Mesoporous silicon flakes were fabricated by anodization from Si substrates. Even though the formation and storage conditions were the same for all wafers, the resulting structures had very different properties. Very high luminescence quantum yields (QYs), over 50%, confirmed by very long luminescence lifetimes, were obtained. This result is significant for two reasons: (i) to date, this QY is the highest obtained for porous silicon (PSi), and (ii) it was obtained for mesoporous silicon with large pores, which typically does not emit light efficiently, as opposed to PSi with small mesopores and microporous silicon. Impregnation of substances into PSi, such as metals for plasmonics and drugs for theranostics, can be more easily achieved with such large mesopores (>15nm diameter), opening the door toward optically active devices. High QYs were correlated to various factors including electrolyte temperature, drying process, and storage condition. The growth of native oxide at the PSi surface participated to the high QYs and their preservation for several years. Samples structures were also characterized by FTIR and TEM.