Department of Physics, National Chung Hsing University , Taichung 402, Taiwan.
Department of Electrophysics, National Chiao Tung University , Hsinchu 300, Taiwan.
ACS Appl Mater Interfaces. 2017 Apr 5;9(13):11985-11992. doi: 10.1021/acsami.6b16412. Epub 2017 Mar 27.
The photoluminescence (PL) and reflectivity characteristics of zinc oxide nanopillars (ZnO-NPs) grown on indium-tin-oxide (ITO)-coated glasses were investigated. The room temperature PL showed bright white-light emission for the undoped ZnO-NPs grown at 600 °C, suggesting the close relation between the optical characteristic and the growth conditions being carried out for obtaining the present ZnO-NPs. The reflectivity of the as-grown ZnO-NPs array was about ∼29% with the wavelength of the incident light ranging from 200 to 1800 nm. Nevertheless, the reflectance reduced significantly to less than 9.9% when a layer of gold (Au) was deposited on ZnO-NPs by sputtering for 5 min, corresponding to more than 65% reduction in Au-coated ZnO-NPs (Au/ZnO-NPs). Moreover, the angle-resolved reflectance measurements on the present Au/ZnO-NPs array show an omnidirectional light-trapping characteristic. These remarkable characteristics, broadband and omnidirectional light-trapping of Au/ZnO-NPs, are attributed to the extended effective optical path of the incident light due to subwavelength scattering resulting from the presence of Au nanoparticles.
研究了在掺锡氧化铟（ITO）涂层玻璃上生长的氧化锌纳米柱（ZnO-NPs）的光致发光（PL）和反射率特性。室温 PL 显示未掺杂 ZnO-NPs 发出明亮的白光，表明光学特性与生长条件密切相关，这些生长条件是为了获得目前的 ZnO-NPs 而进行的。生长的 ZnO-NPs 阵列的反射率约为∼29%，其入射光的波长范围为 200 至 1800nm。然而，当通过溅射在 ZnO-NPs 上沉积 5 分钟的金（Au）层时，反射率显著降低至小于 9.9%，对应于 Au 涂覆的 ZnO-NPs（Au/ZnO-NPs）的反射率降低了超过 65%。此外，对当前 Au/ZnO-NPs 阵列的角度分辨反射率测量显示出全向光捕获特性。Au/ZnO-NPs 的这些显著特性，即宽带和全向光捕获，归因于由于存在金纳米颗粒导致的亚波长散射引起的入射光的有效光程延长。
