用金纳米粒子修饰硅纳米线及复合结构的光谱性质研究

在溶液中以正己硫醇作稳定剂, 利用HAuCl4与HF处理后的硅纳米线(SiNWs)的氧化还原反应, 在SiNWs表面负载金纳米粒子(AuNPs). 通过调整HAuCl4的浓度, 得到了AuNPs粒径从3.2到7.0 nm的AuNPs/SiNWs复合结构, 并对这种复合结构进行了紫外-可见吸收光谱和荧光光谱研究. 紫外-可见吸收光谱研究表明, 负载不同粒径的AuNPs的SiNWs在530～580 nm间有明显的由AuNPs表面等离子体共振引起的吸收, 且随着AuNPs粒径的增加, 该吸收峰发生红移. 负载前后的荧光光谱表明, 在红光和绿光区负载AuNPs的SiNWs的荧光峰与HF处理后SiNWs的荧光峰峰形相当, 峰位变化不大; 但在蓝光区, 不同于HF处理前后SiNWs的发射峰(464 nm左右), 负载了AuNPs的SiNWs在423 nm的位置处出现了强荧光峰, 这个峰是AuNPs费米能级的电子与sp或d带的空穴辐射复合产生的.

Silicon Nanowires Decorated with Au Nanoparticles and Their Spectroscopic Properties

Au nanoparticles (AuNPs) were loaded on silicon nanowires (SiNWs) via the redox reaction between HAuCl4 and HF-treated SiNWs in the presence of hexanethiol as stabilizer. As a result, AuNPs/SiNWs composites with AuNPs of varied sizes from 3.2 to 7.0 nm were obtained by adjusting the HAuCl4 concentration. The absorption and emission properties of the AuNPs/SiNWs were investigated by UV-visible and fluorescence spectroscopy methods. UV-vis spectra indicated that the AuNPs/SiNWs composites had absorption bands ranging from 530 to 580 nm, which were attributed to the AuNPs surface plasmon resonance (SPR). The SPR band was observed to red-shift with increase of the AuNPs size. Fluorescence spectra indicated that the fluorescence profile and peak position of the AuNPs/SiNWs were not changed significantly compared to the HF-treated SiNWs in the red and green regions. In the blue region, however, different from as-grown SiNWs and the HF-treated SiNWs with an emission at around 464 nm, an intense fluorescence band was observed at 423 nm, which was supposed to result from radiative recombination of Fermi level electrons and sp- or d-band holes in AuNPs.