报告题目：Energy transfers in SiO2:Er sensitized with Si nanocrystals
报告人：Prof. Tom Gregorkiewicz, Van der Waals-Zeeman Institute, University of Amsterdam, The Netherlands
时间：2010年5月27日14:00
地点：硅材料国家重点实验室会议室（半导体厂内3号楼）
报告摘要：
SiO2 matrix doped with Er3+ ions and Si nanocrystals (Si NCs) is intensively investigated as an interesting system where room temperature 1.5 um Er-related emission can efficiently be induced by nonresonant excitation. It has been concluded that dispersion of Si nanocrystals in Er-doped SiO2 matrix SiO2:(Er, Si NCs) combines, to a certain extent, positive features of Er-doped crystalline Si with those of Er-doped SiO2: (i)In contrast to the situation for SiO2 :Er, introduction of Si NCs enables indirect excitation of Er3+ ions.This process is nonresonant and relatively efficient with an effective excitation cross section of σ～10−17 –10−16 cm−2, which represents an increase by a factor of 103 incomparison to SiO2 :Er. (ii)In contrast to the situation in crystalline Si:Er, emission from Er3+ ions does not suffer from thermal quenching and is readily observed at room temperature, similar to SiO2 :Er.
we have studied, in depth, temporal details of emission bands from SiO2:(Er, Si NCs). Using optical excitation with nanosecond pulses and time-correlated photon-counting detection mode, we resolve true kinetics of emissions related to Si NCs and Er3+ ions present in the investigated material. Based on this information, we propose a complete microscopic scenario of energy-transfer processes in the SiO2 :(Er, Si NCs) system. The chosen approach allows us to identify emissions from most of the Er dopants available in the material. Using a theoretical model, we discuss microscopic aspects of energy-transfer processes between Si NCs and Er3+ ions in relation to their(mutual)location in the SiO2 matrix.
T.Gregorkiewicz教授简介：
Prof. Gregorkeiwicz got his PH.D. at the Institute of Physics, Polish Academy of Sciences, Warsaw 1980. Then he worked at Institute of Physics, Polish Academy of Sciences till 1988. After 1989, he went to University of Amsterdam in the Faculty of Science as associated and full professor. Prof. Gregorkeiwicz is one of the famous scientists in the field of silicon photonics. He organized 2 of EMRS conferences in 2000 and 2006. He also organized 2003 and 2005 MRS conferences for silicon photonics. Now, he has published 187papers, including 1 nature photonics，12 PRL and 40 PRB.
