Department of Electrical and Computer Engineering, University of Minnesota, Minneapolis, MN 55455, USA.
Nanotechnology. 2012 Oct 5;23(39):395205. doi: 10.1088/0957-4484/23/39/395205. Epub 2012 Sep 12.
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.
我们报告了硅纳米晶体（SiNCs）的光致发光（PL）性能的长期环境稳定性。我们在两步等离子体反应器中制备了六氟化硫（SF6）刻蚀的 SiNCs，并研究了它们在空气中对紫外线照射的 PL 稳定性。与具有氢化表面的 SiNCs 不同，SF6刻蚀的 SiNCs 在表面氧化的情况下，在延长的紫外线照射下不会发生光漂白。此外，SF6刻蚀的 SiNCs 在加热至 160°C 时，其 PL 量子产率也保持稳定。SF6刻蚀的 SiNCs 的热稳定性和紫外线稳定性以及高达约 50%的 PL 量子产率，使它们成为用于紫外线下转换以提高太阳能电池效率的有吸引力的候选材料。电子顺磁共振表明，SF6刻蚀的 SiNCs 的缺陷态密度较低，无论是在形成时还是在空气中室温氧化后。
