Temperature dependence of steady and time-resolved photoluminescence in Si quantum dots/SiO₂ superlattices

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• 作者：Wei Yu ; Huina Feng ; Jin Wang ; Wanlei Dai ; Xiang Yu ; Jiawei Zhang ; Weidong Lai ; Guangsheng Fu
• 关键词：Superlattices ; Time-resolved photoluminescence ; Singlet-triplet state
• 刊名：Physica B
• 出版年：1 February, 2014
• 年：2014
• 卷：434
• 期：Complete
• 页码：177-180
• 全文大小：1205 K

文摘

Superlattices of amorphous silicon rich oxide (a-SiO_x) and silicon dioxide (SiO₂) have been deposited by plasma enhanced chemical vapor deposition technique, and Si quantum dots (Si-QDs) are obtained in the a-SiO_x layers by the following annealing treatment. Steady and time-resolved photoluminescence (PL) spectra at different temperatures are measured. Two broad PL bands located in the regions of 1.2-1.6 eV and 2.1-3.1 eV are obtained at low temperature, and they are defined as S band and F band, respectively. The PL decay time of the samples increases rapidly with decreasing temperature. Analyses show that the recombination dynamics of S band is related to the dispersive motion of excitons, and its PL lifetime is associated with an upper level singlet state and a lower level triplet state, while that of the F band is related to the recombination of oxygen related defects.