nanotehnoloogia, nanoteknologia, nanotechnologija, nanotehnologijas, nanoteknologija,
nanotechnologii, nanotecnologia, nanotehnologijo, nanoteknik
Jorden van Dam, researcher at the Kavli Institute
of Nanoscience Delft, has succeeded in largely controlling
the transportation of electrons in semiconductor
nanowires. Van Dam moreover discovered how to observe
a divergent type of supercurrent in these wires.
Nanowires have superior electronic properties which
in time could improve the quality of our electronics.
On Tuesday, June 13, Van Dam will receive his PhD
degree at Delft University of Technology based on
During his PhD research, Jorden van Dam focused
on semiconductor nanowires. These are extremely thin
wires (1-100 nanometers thick) made of, for example,
the material indiumarsenide, which has superior electronic
properties. The integration of these high quality
nanowires with the now commonly used silicium technology
offers intriguing possibilities for improving our
electronics in future. According to Van Dam, in recent
years many possible applications for semiconductor
nanowires have emerged, such as in lasers, transistors,
LEDs and bio-chemical sensors. Philips is one of
the companies that is conducting intensive research
into the possibilities for semiconductor nanowires
in specific applications.
Dam - who during his PhD research co-authored articles
that were published in Nature and Science - was able
to make a so-called quantum dot in a semiconductor
nanowire (this is done at extremely low temperatures).
These quantum dots can be regarded as artificial
atoms and in the distant future will serve as building
blocks for super-fast quantum computers.
In a quantum dot, a number of electrons can be ‘confined'. The magnificence
of Van Dam's research is the total control he has managed to gain over the
number of electrons that can be confined in a quantum dot. He can control this
number by means of an externally introduced charge. A crucial factor for the
extreme degree of control that Van Dam has achieved is the quality (for example
the purity) of the nanowires, which were supplied by Philips. It is above all
the quality of the material used (wires and electrodes) that was greatly improved
during Van Dam's research.
The research also produced new physical observations.
In the improved nanowires, Van Dam achieved for the
first time the realisation and observation of a (theoretically
already predicted) divergent type of supercurrent
(a supercurrent is the current that occurs in superconductivity).
In a quantum dot, the electrons normally pass through
one by one. In superconductivity, the passage of
electrons occurs in pairs. Van Dam, with the help
of superconductor electrodes, has now achieved a
supercurrent in the quantum dot, whereby the pairs
of electrons pass through one by one.
Van Dam has also - under specific conditions - achieved a reversal in the direction
of the supercurrent. He is able to control this reversal by varying the number
of electrons confined in the quantum dot. With this, the Delft University of
Technology researcher has achieved a largely controllable superconductor connection
in semiconductor nanowires.
Jorden van Dam,
T: +31 15 278 6085,
Frank Nuijens, science information officer,
T: +31 15 278 4259,