Overview
The core element of
the Terahertz camera is the
ultra-sensitive sensor.
We use
semiconductor quantum
dot (QD) coupled to single electron transistor (SET) to detect individual THz
photons, see the picture. The QD is formed in 2DEG channel by mesa patterning
and biased gates, see (A). The aluminum SET is formed at the top of the QD. The SET
senses change of the potential when electron is excited out of QD upon
absorption of the THz photon, see (B). Each event of the electron excitation is seen as
telegraph-like jump of the SET conductance, see (C). The conductance is recovered back
when the electron comes back and the QD is relaxed. Thus one can use this system
to detect THz photon by counting switches of the SET conductance. The device
device is a development of the
original THz sensor proposed by us a few years ago. Two remaining component
of the Terahertz camera, optical system and spectral filters, are also on the
list of the development at RHUL.
Research and skill
The
project includes
theoretical analysis and nanofabrication components of
the
Terahertz camera
at RHUL
Nanotechnology centre
. The operation of the devices and related physical
phenomena are studied at our low temperatures facilities. Scanning
Electron Microscope picture of the sensor fabricated and studied at RHUL is
shown in a picture. The QD is formed in 2DEG mesa channel by negatively biasing two
cross gates (CG). The QD is capacitively coupled to the aluminum SET sitting at the top
of mesa channel.
Collaborations
The project is carried out in collaboration with
Tokyo University and a group at
National Physical Laboratory of UK.
Finance
The research is supported by EPSRC GR/N37407/01/(P), “ Novel High Sensitive Hybrid Detector in Far-Infrared Range”, July 2000-July 2002; Japan Science and Technology Corp, “Development of Infrared Detectors and Exploration of Near-Field Infrared microscopy”, April 2002-March 2006; Sixth Framework Programme (FP6) Integrated Project “TERAEYE: Q-Dot Terahertz Security Imager/Scanner”, September 2006- September 2010