Photoluminescence Quantum Yield in Ensembles of Si Nanocrystals. Issue 4 (30th January 2017)

• Record Type: Journal Article
• Authors: Chung, Nguyen Xuan; Limpens, Rens; Gregorkiewicz, Tom
• Is Part Of: Advanced optical materials. Volume 5:Issue 4(2017:Apr.)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-01-30
• Subjects: excitation dependence -- optimal size -- photoluminescence quantum yield -- silicon nanocrystals -- size dependence; Optical materials -- Periodicals; Photonics -- Periodicals; 620.11295
• DOI: 10.1002/adom.201600709
• Languages: English
• ISSNs: 2195-1071

Abstract

Abstract : This study investigates the photoluminescence quantum yield for co‐sputtered solid‐state dispersions of Si nanocrystals in SiO2 with different size and density, and concludes that the absolute value of the photoluminescence quantum yield shows a varied dependence on the excitation energy. Physical mechanisms influencing the photoluminescence quantum yield at different excitation energy ranges are considered. Based on the experimental evidence, this study proposes a generalized description of the excitation dependence of photoluminescence quantum yield of Si nanocrystals in SiO2, and concludes on the important role of impact excitation by hot carriers and parasitic absorption at high and low excitation energy ranges, respectively. Abstract : For silicon nanocrystals in an SiO2 matrix, the increase of the ensemble photoluminescence quantum yield in the low excitation energy range originates from the parasitic absorption. In the high excitation energy range, the photoluminescence quantum yield gradient depends on the competition between the spaced‐separated‐quantum cutting effect and trapping of hot carriers.