Plasmonic enhancements of photoluminescence in hybrid Si nanostructures with Au fabricated by fully top-down lithography.

Koudo Nakaji,Takayuki Kiba,Hao Li,Makoto Igarashi,Seiji Samukawa,Akihiro Murayama

doi:10.1186/1556-276x-7-629

Koudo Nakaji, Takayuki Kiba + Show 4 more

Open Access

https://doi.org/10.1186/1556-276x-7-629

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Abstract

The authors study plasmonic enhancements of photoluminescence (PL) in Si nanodisk (ND) arrays hybridized with nanostructures such as nanoplates of Au, where these hybrid nanostructures are fabricated by fully top-down lithography: neutral-beam etching using bio-nano-templates and high-resolution electron-beam lithography. The separation distance between the Si ND and Au nanostructure surfaces is precisely controlled by inserting a thin SiO2 layer with a thickness of 3 nm. We observe that PL intensities in the Si NDs are enhanced by factors up to 5 depending on the wavelength by integrating with the Au nanoplates. These enhancements also depend on the size and shape of the Au nanoplates.

Highlights

Plasmonic effects induced by metallic nanostructures, such as remarkable enhancements of the intensity of photoluminescence (PL) in semiconductor nanostructures, are very attractive because optical responses of the semiconductor nanostructures can be controlled in the relatively wide spectral range [1,2,3,4,5]
We have observed plasmonic enhancements of PL in hybrid nanostructures of Si NDs with Au nanoplates, where the Au nanoplate is separated from the surface of the Si ND array by inserting a SiO2 layer with a thickness of 3 nm
We demonstrate that PL intensities in the Si NDs are enhanced by integrating the Au nanoplates, depending on the wavelength

Summary

Introduction

Plasmonic effects induced by metallic nanostructures, such as remarkable enhancements of the intensity of photoluminescence (PL) in semiconductor nanostructures, are very attractive because optical responses of the semiconductor nanostructures can be controlled in the relatively wide spectral range [1,2,3,4,5]. Fully topdown fabrication of semiconductor nanostructures exhibiting the plasmonic effects has not been established yet because the plasmonic effects appear only when optically active nanomaterials are close to the metallic nanostructures, typically at a distance of 10 nm. Conventional lithography techniques are not applicable to the fabrication of the plasmon-coupled hybrid nanostructures of semiconductors with metals. To solve this problem, we have employed Si nanodisks (NDs) fabricated by damage-free neutral-beam etching using bio-nano-templates [6,7,8]. A closely packed twodimensional alignment of the Si ND with a diameter of 10 nm and interspacing of 2 nm was formed, where the

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