Carbon Nanotube Quantum Dots as THz Detectors
Abstract
In this project we developed very sensitive broadband THz detectors using carbon nanotube quantum dots coupled to antenna-shaped source and drain electrodes. The sensing mechanism is photon-assisted tunneling and leads to a counterintuitive effect: the THz irradiation reduces the effective temperature of the electrons in the dot and drastically increases the height of the Coulomb blockade peaks, greatly enhancing the device performance. This type of detector is very attractive because 1) it is highly sensitive (THz power in the femtowatt range can be easily detected), 2) unlike other THz detectors such as bolometers, it has a frequency dependent response, with spectral resolution within about a tenth of THz via photon assisted tunneling, that is inelastic tunneling of single electrons through the dot via absorption or emission of photons. We also find a strongly enhanced response that orthodox theories of photon assisted tunneling fail to quantitatively explain. We suggest that this effect is due to tunneling through excited states and non-equilibrium cooling in the presence of THz radiation.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 14, 2012
- Accession Number
- ADA575718
Entities
People
- Paola Barbara
Organizations
- Georgetown University