Atomic layer lithography of wafer-scale nanogap arrays for extreme confinement of electromagnetic waves

Xiaoshu Chen, Hyeong Ryeol Park, Matthew Pelton, Xianji Piao, Nathan C. Lindquist, Hyungsoon Im, Yun Jung Kim, Jae Sung Ahn, Kwang Jun Ahn, Namkyoo Park, Dai Sik Kim, Sang Hyun Oh

Research output: Contribution to journalArticlepeer-review

290 Scopus citations

Abstract

Squeezing light through nanometre-wide gaps in metals can lead to extreme field enhancements, nonlocal electromagnetic effects and light-induced electron tunnelling. This intriguing regime, however, has not been readily accessible to experimentalists because of the lack of reliable technology to fabricate uniform nanogaps with atomic-scale resolution and high throughput. Here we introduce a new patterning technology based on atomic layer deposition and simple adhesive-tape-based planarization. Using this method, we create vertically oriented gaps in opaque metal films along the entire contour of a millimetre-sized pattern, with gap widths as narrow as 9.9 Å, and pack 150,000 such devices on a 4-inch wafer. Electromagnetic waves pass exclusively through the nanogaps, enabling background-free transmission measurements. We observe resonant transmission of near-infrared waves through 1.1-nm-wide gaps (λ/1,295) and measure an effective refractive index of 17.8. We also observe resonant transmission of millimetre waves through 1.1-nm-wide gaps (λ/4,000,000) and infer an unprecedented field enhancement factor of 25,000.

Original languageEnglish
Article number2361
JournalNature Communications
Volume4
DOIs
StatePublished - 2013

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