Experts master defects in semiconductors

Date:
November 5, 2021
Source:
City College of New York
Summary:
Researchers have discovered a novel way to manipulate defects in
semiconductors. The study holds promising opportunities for novel
forms of precision sensing, or the transfer of quantum information
between physically separate qubits, as well as for improving the
fundamental understanding of charge transport in semiconductors.



FULL STORY ========================================================================== Researchers at The City College of New York have discovered a novel
way to manipulate defects in semiconductors. The study holds promising opportunities for novel forms of precision sensing, or the transfer
of quantum information between physically separate qubits, as well
as for improving the fundamental understanding of charge transport in semiconductors.


========================================================================== Using laser optics and confocal microscopy, the researchers demonstrated
that they could make one defect eject charges -- holes -- under laser illumination allowing the other defect several micrometers away to
catch them. The charge state of the latter defect is then altered from
a negative into a neutral one via a charge capture.

The study utilized a special type of point defect -- nitrogen-vacancy
center in diamond. These color centers possess spin -- an inherent form of angular momentum carried by elementary particles -- making them attractive
for quantum sensing and quantum information processing. The researchers
used a specific protocol to filter out the charges originating solely
from the nitrogen vacancy based on its spin projection.

"The key was isolating the source defect, with only the nitrogen
vacancy being present, which we achieved by making charge ejection
conditional on the defect's spin state" said Artur Lozovoi, physics postdoctoral researcher in CCNY's Division of Science and the paper's
lead author. "Another crucial aspect was having a "clean" diamond with
as few defects as possible. Then, the long- range attractive Coulombic interaction between a defect and a hole substantially increases the
probability of the charge going towards the target, which ultimately
made our observations possible." The present study uncovered that in
the clean material the charge transport efficiency is a thousand times
higher than observed in previous experiments, a phenomenon characterized
by the researchers as a "giant capture cross-section." This discovery
could pave the way towards establishing a quantum information bus between
color center qubits in semiconductors.

"This process of a charge capture by an individual defect
has only been described theoretically before," added
Lozovoi. "There is now an experimental platform that enables
us to look into how these defects interact with free charges in
crystals and how we can use it for quantum information processing." ========================================================================== Story Source: Materials provided by City_College_of_New_York. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Artur Lozovoi, Harishankar Jayakumar, Damon Daw, Gyorgy Vizkelethy,
Edward Bielejec, Marcus W. Doherty, Johannes Flick, Carlos
A. Meriles.

Optical activation and detection of charge transport between
individual colour centres in diamond. Nature Electronics, 2021;
4 (10): 717 DOI: 10.1038/s41928-021-00656-z ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/11/211105134618.htm

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