Strainoptronics: A new way to control photons
Researchers create first efficient 2D material photodetector for telecom wavelengths

Date:
June 22, 2020
Source:
George Washington University
Summary:
Researchers discovered a new way to engineer optoelectronic
devices by stretching a two-dimensional material on top of a
silicon photonic platform.



FULL STORY ========================================================================== Researchers discovered a new way to engineer optoelectronic devices
by stretching a two-dimensional material on top of a silicon photonic
platform.

Using this method, coined strainoptronics by a team led by George
Washington University professor Volker Sorger, the researchers
demonstrated for the first time that a 2D material wrapped around a
nanoscale silicon photonic waveguide creates a novel photodetector that
can operate with high efficiency at the technology-critical wavelength
of 1550 nanometers.


==========================================================================
Such new photodetection can advance future communications and computer
systems, especially in emerging areas such as machine learning and
artificial neural networks.

The ever-increasing data demand of modern societies requires a more
efficient conversion of data signals in the optical domain, from fiber
optic internet to electronic devices, like a smartphone or laptop. This conversion process from optical to electrical signals is performed by
a photodetector, a critical building block in optical networks.

2D materials have scientific and technologically relevant properties
for photodetectors. Because of their strong optical absorption,
designing a 2D material-based photodetector would enable an improved photo-conversion, and hence more efficient data transmission and telecommunications. However, 2D semiconducting materials, such as those
from the family of transition metal dichalcogenides, have, so far, been
unable to operate efficiently at telecommunication wavelengths because
of their large optical bandgap and low absorption.

Strainoptronics provides a solution to this shortcoming and adds an
engineering tool for researchers to modify the electrical and optical properties of 2D materials, and thus the pioneered 2D material-based photodetectors.

Realizing the potential of strainoptronics, the researchers
stretched an ultrathin layer of molybdenum telluride, a 2D material semiconductor, on top of a silicon photonic waveguide to assemble a novel photodetector. They then used their newly created strainoptronics "control knob" to alter its physical properties to shrink the electronic bandgap, allowing the device to operate at near infrared wavelengths, namely at
the telecommunication (C-band) relevant wavelength around 1550 nm.

The researchers noted one interesting aspect of their discovery:
the amount of strain these semiconductor 2D materials can bear is
significantly higher when compared to bulk materials for a given amount
of strain. They also note these novel 2D material-based photodetectors
are 1,000 times more sensitive compared to other photodetectors using
graphene. Photodetectors capable of such extreme sensitivity are useful
not only for data communication applications but also for medical sensing
and possibly even quantum information systems.

"We not only found a new way to engineer a photodetector, but also
discovered a novel design methodology for optoelectronic devices, which
we termed 'strainoptronics.' These devices bear unique properties for
optical data communication and for emerging photonic artificial neural
networks used in machine learning and AI," said Volker Sorger, associate professor of electrical and computer engineering at GW.

"Interestingly, unlike bulk materials, two-dimensional materials are particularly promising candidates for strain engineering because they can withstand larger amounts of strain before rupture. In the near future, we
want to apply strain dynamically to many other two-dimensional materials
in the hopes of finding endless possibilities to optimize photonic
devices," said Rishi Maiti, postdoctoral fellow in the electrical and
computer engineering department at GW.


========================================================================== Story Source: Materials provided by George_Washington_University. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. R. Maiti, C. Patil, M. A. S. R. Saadi, T. Xie, J. G. Azadani,
B. Uluutku,
R. Amin, A. F. Briggs, M. Miscuglio, D. Van Thourhout,
S. D. Solares, T.

Low, R. Agarwal, S. R. Bank, V. J. Sorger. Strain-engineered high-
responsivity MoTe2 photodetector for silicon photonic integrated
circuits. Nature Photonics, 2020; DOI: 10.1038/s41566-020-0647-4 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200622133039.htm

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