Fabrication of free-standing subwavelength metal-insulator-metal gratings using high-aspect-ratio nanoimprint techniques

摘要

In this paper, we report on the construction of a free-standing metal-insulator-metal (MIM) subwavelength grating by nanoimprint and lift-off techniques, which can be used as a plasmonic color filter for imaging a multicolor spectrum. The free-standing subwavelength grating was designed to be composed of Al (50 nm)-SiO2 (150 nm)-Al (50 nm) layers, and the thickness of the SiO2 layer determined the wavelength selectivity for the color filter. The residual-free nanoimprint with an aspect ratio of 6 : 1 was applied in the lift-off process to the formation of MIM gratings. We successfully developed subwavelength MIM gratings with heights of more than 200 nm. We also demonstrated the fabrication of a free-standing MIM grating without lateral stiction, which was expected to improve the wavelength selectivity of a free-standing plasmonic color filter. (C) 2016 The Japan Society of Applied Physics