Open Accessn-type Ge/Si antennas for THz sensing
Author(s) -
Carlos Alvarado Chavarin,
Elena Hardt,
Soenke Gruessing,
Oliver Skibitzki,
I. Costina,
Davide Spirito,
W. Seifert,
Wolfgang M. Klesse,
Costanza Lucia Manganelli,
Changjiang You,
Julia Flesch,
Jacob Piehler,
Mauro Missori,
Leonetta Baldassarre,
Bernd Witzigmann,
Giovanni Capellini
Publication year - 2021
Publication title -
optics express
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.418382
Subject(s) - terahertz radiation , optoelectronics , plasmon , materials science , resonator , silicon nitride , optics , silicon , physics
Ge-on-Si plasmonics holds the promise for compact and low-cost solutions in the manipulation of THz radiation. We discuss here the plasmonic properties of doped Ge bow-tie antennas made with a low-point cost CMOS mainstream technology. These antennas display resonances between 500 and 700 GHz, probed by THz time domain spectroscopy. We show surface functionalization of the antennas with a thin layer of α-lipoic acid that red-shifts the antenna resonances by about 20 GHz. Moreover, we show that antennas protected with a silicon nitride cap layer exhibit a comparable red-shift when covered with the biolayer. This suggests that the electromagnetic fields at the hotspot extend well beyond the cap layer, enabling the possibility to use the antennas with an improved protection of the plasmonic material in conjunction with microfluidics.