Environmental photostability of SF 6 -etched silicon nanocrystals

We report on the long-term environmental stability of the photoluminescent (PL) properties of silicon nanocrystals (SiNCs). We prepared sulfur hexafluoride (SF 6 ) etched SiNCs in a two-stage plasma reactor and investigated their PL stability against UV irradiation in air. Unlike SiNCs with hydrogen-passivated surfaces, the SF 6 -etched SiNCs exhibit no photobleaching upon extended UV irradiation despite surface oxidation. Furthermore, the PL quantum yield also remains stable upon heating the SF 6 -etched SiNCs up to 160 °C. The observed thermal and UV stability of SF 6 -etched SiNCs combined with their PL quantum yields of up to ∼50% make them attractive candidates for UV downshifting to enhance the efficiency of solar cells. Electron paramagnetic spin resonance indicates that the SF 6 -etched SiNCs have a lowered density of defect states, both as-formed and after room temperature oxidation in air.

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2012-09-12 10:07:04

Source: http://nanochemistry.blogspot.com/2012/09/environmental-photostability-of-sf-6.html