Tailoring Optical Properties of Silicon Nanowires by Au Nanostructure Decorations: Enhanced Raman Scattering and Photodetection

• Published in: Journal of physical chemistry. C Vol. 116; no. 7; pp. 4416 - 4422
• Main Authors: Chen, Renjie, Li, Dehui, Hu, Hailong, Zhao, Yanyuan, Wang, Ying, Wong, Nancy, Wang, Shijie, Zhang, Yi, Hu, Jun, Shen, Zexiang, Xiong, Qihua
• Format: Journal Article
• Language: English
• Published: Columbus, OH American Chemical Society 23.02.2012
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Low-dimensional structures (superlattices, quantum well structures, multilayers): structure, and nonelectronic properties; Materials science; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of low-dimensional, mesoscopic, and nanoscale materials and structures; Physics; Quantum wires; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Nucleation; Optoelectronic properties; Photocurrents; Nanostructures; Surface plasmons; Nanoprism; Nanoparticles; Anisotropy; Raman scattering; Optical properties; Dimers; Silicon; Nanowires; Photoconductivity; Nanorod; Nanostructured materials; Heterostructures
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/jp210198u

Metallic nanoparticles (NPs) decorated semiconductor nanowires (NWs) heterostructures show significant promise in enhanced optical and opto-electrical properties due to the coupling of surface plasmon to nanowires. Here, we demonstrate a galvanic displacement based strategy to achieve in situ nucleation of Au nanoparticles and then postgrowth into higher order Au nanostructures such as dimers, nanorods, and nanoprisms along the same Si nanowires (SiNWs). The presence of Au nanostructures significantly enhances the optical properties of nanowires. Particularly, a 24 times enhancement of Si Raman scattering signal was achieved with a Au dimer decoration. A Au nanorod aligned in parallel along nanowire strongly enhances the anisotropy of Si Raman scattering, with more than 28 times stronger signal under parallel polarization than that under perpendicular polarization, demonstrating for the first time the surface plasmon enhanced antenna effect. In addition, we demonstrate that surface plasmon enhances photocurrent of SiNW by almost 100%, which is higher than previous reports. Our studies show that SiNWs decorated with metallic nanostructures by in situ galvanic displacement exhibit significant promise toward high efficiency photodetection and light harvesting applications.