Metallic carbon nanotube quantum dots with broken symmetries as a platform for tunable terahertz detection
Generating and detecting radiation in the technologically relevant range of the so-called terahertz gap (0.1–10 THz) is challenging because of a lack of efficient sources and detectors. Quantum dots in carbon nanotubes have shown great potential to build sensitive terahertz detectors, usually based...
Gespeichert in:
Veröffentlicht in: | Applied physics reviews 2021-06, Vol.8 (2) |
---|---|
Hauptverfasser: | , , , , , , , , |
Format: | Artikel |
Sprache: | eng |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Generating and detecting radiation in the technologically relevant range of the so-called
terahertz gap (0.1–10 THz) is challenging because of a lack of efficient sources and
detectors. Quantum dots in carbon nanotubes have shown great potential to build sensitive
terahertz detectors, usually based on photon-assisted tunneling. A recently reported
mechanism combining resonant quantum dot transitions and tunneling barrier asymmetries
results in a narrow linewidth photocurrent response with a large signal-to-noise ratio
under weak THz radiation. That device was sensitive to one frequency, corresponding to
transitions between equidistant quantized states. In this work we show, using numerical
simulations together with scanning tunneling spectroscopy studies of a defect-induced
metallic zigzag single-walled carbon nanotube quantum dot, that breaking simultaneously
various symmetries in metallic nanotube quantum dots of arbitrary chirality strongly
relaxes the selection rules in the electric dipole approximation and removes energy
degeneracies. This leads to a richer set of allowed optical transitions spanning
frequencies from 1 THz to several tens of THz, for a ∼10 nm quantum dot. Based on these
findings, we propose a terahertz detector device based on a metallic single-walled carbon
nanotube quantum dot defined by artificial defects. Depending on its length and contacts
transparency, the operating regimes range from a high-resolution gate-tunable terahertz
sensor to a broadband terahertz detector. Our calculations indicate that the device is
largely unaffected by temperatures up to 100 K, making carbon nanotube quantum dots with
broken symmetries a promising platform to design tunable terahertz detectors that could
operate at liquid nitrogen temperatures. |
---|---|
ISSN: | 1931-9401 1931-9401 |
DOI: | 10.1063/5.0018944 |