Hyun Gu Kim

Fabrication of 50 nm scale Pt nanostructures by block copolymer (BCP) and its characteristics of surface-enhanced Raman scattering (SERS)

Surface-enhanced Raman scattering (SERS) represents an important phenomenon that can solve the low signal intensity of Raman spectroscopy, applied as a bio and chemical sensor and analyzer. The SERS effect can be varied with the substrate structure. In this study, we investigated the effect of various Pt nanostructures (e.g., Pt nanoholes, Pt nanorods, and Pt nanotubes) on the sensitivity of SERS. We fabricated 50 nm-scale Pt nanostructures with different heights with a self-aligned block copolymer (BCP) process composed of the self-assembly of BCP, Pt atomic layer deposition, and reactive ion etching of a silicon substrate and Pt. Our investigation of the SERS effect with rhodamine 6G showed a significant dependence on the shape (but not the height) of the nanostructure. Among the different Pt nanostructures investigated, Pt nanotubes (possessing the structural characteristics of nanoholes and nanorods) showed the highest SERS effect, while Pt nanoholes showed the lowest SERS effect.

Growth of Atomic Layer Deposition Platinum on TiO 2

Atomic layer deposition (ALD) is essential for the fabrication of nanoscale electronic devices because it has excellent conformality, atomic scale thickness control, and large area uniformity. Metal thin films are one of the important material components for electronic devices as a conductor. As the size of electronic devices shrinks, the thickness of metal thin films is decreased down to few nanometers, and the metal films become non-continuous due to inherent island growth of metal below a critical thickness. So, fabrication of continuous metal thin films by ALD is fundamentally and practically important. Since ALD films are grown through self-saturated reactions between precursors on surface, initial growth characteristics significantly depend on the surface properties and the selection of precursors. In this work, we investigated ALD Pt on TiO2 substrate by using trimethyl-methyl-cyclopentadienyl-Platinum (MeCpPtMe3) precursor and O3 reactant. By using O3 instead of O2, initial nucleation rate of ALD Pt was increased on TiO2 surface, resulting in formation of continuous thin Pt films. Morphologies of ALD Pt on TiO2 were characterized by using Scanning Electron Microscope (SEM) and Energy-Dispersive X-ray Spectroscopy (EDS). Crystallinity of ALD Pt on TiO2 correlated with its growth characteristics was analyzed by X-Ray Diffraction (XRD).