Open AccessDynamic electrical measurement of biomolecule behavior via plasmonically-excited nanogap fabricated by electromigration
Author(s) -
Akihiro Morita,
Takayuki Sumitomo,
Akio Uesugi,
Koji Sugano,
Yoshitada Isono
Publication year - 2021
Publication title -
nano express
Language(s) - English
Resource type - Journals
ISSN - 2632-959X
DOI - 10.1088/2632-959x/abe9c0
Subject(s) - materials science , plasmon , nanopore , biomolecule , electromigration , optoelectronics , nanotechnology , excitation , laser , raman spectroscopy , electrode , chemistry , optics , physics , composite material , engineering , electrical engineering
The dynamic motion of DNA oligomers at the nanoscale gap between nanoelectrodes is measured under plasmonic excitation using laser irradiation. The use of a nanogap enables highly sensitive detection of individual molecules using an electrical readout or an optical readout such as Raman spectroscopy. However, the target molecule must reach the nanogap in order to be detected. This study focuses on the use of plasmonic excitation to trap molecules at the nanogap surface. The nanogap electrode is fabricated by electromigration and is, therefore, a much smaller nanogap than the top-down fabrication in the conventional plasmonic trapping studies. To demonstrate the individual molecule detection and to investigate the molecular behavior, the molecules are monitored using an electrical readout under a bias voltage instead of an optical readout used in the conventional studies. The conductance change due to DNA oligomer penetration to the nanogap is observed with the irradiated light intensity of over 1.23 mW. The single-molecule detection is confirmed irradiating the laser to the nanogap. The results suggest that DNA oligomers are spontaneously attracted and concentrated to the nanogap corresponding to the detection point, resulting in high detection probability and sensitivity.