Nano-Electronics/Spintronics and Nano-Optics

◈  연  사 : 김 광 수 교수 (포항공대 화학과)

◈ 일  시 : 2010년 4월 9일 (금) 오후 2:45 ~ 4:15

◈ 장  소 : LG동 강당

◈ 초청자 : 권 오 대 교수 (T.2212)

Abstract

I discuss the electron and spin transport phenomena in nanodevices [1]. Given that an intricate problem in molecular electronics is to control the molecule-electrodes contacts, I will show that carbon-based electrodes are able to provide pristine molecular characteristics much better than Au or Ru electrodes. Graphene nanoribbon spin-valve devices are found to show the super magnetoresistance behavior, i.e., the ideal behaviour with perfect transmission/reflection for the parallel/anti-parallel spin configuration [2]. The device is able to play a role as a spin filter which selectively transmits near 100% spin-polarized current. Our recent work on the graphene synthesis and transfer [3] and the enhanced resonance Raman spectroscopy on the graphene substrate through nano-scale lenses are also addressed for the futuristic graphene nanotechnology.

Then, I discuss nanoscale lenses showing the super-resolution. Despite numerous studies of miniaturized lenses, no serious studies have been undertaken on lenses for subwavelength nano-optics. Thus, we fabricate well-defined self-assembled organic nanoscale lenses with sphere-derived shapes of radius from 50 to 3000 nm [4]. These nanoscale spherical lenses show near-field high-resolution. In contrast to geometrical optics lenses, they exhibit curvilinear trajectories of light, resulting in remarkably short near-field focal lengths. This in turn results in near-field magnification which is able to resolve features beyond the diffraction-limit. Such spherical nanolenses provide new pathways for lens-based near-field focusing and high-resolution optical imaging at very low intensities.

[1] (a) W. Y. Kim, et al. Acc. Chem. Res. 43, 111 (2010). (b) W. Y. Kim, et al. Chem. Soc. Rev. 38, 2319 (2009). (c) D. Cheng, et al. Phys. Rev. Lett. 96, 096104 (2006).

[2] W. Y. Kim, K. S. Kim, Nature Nanotech. 3, 408 (2008).

[3] K. S. Kim, et al. Nature 457, 706 (2009).

[4] Lee, J. Y. et al. Nature 460, 498 (2009).