Tech Briefs Magazine - October 2021 - 40

Manufacturing &
Prototyping
nanostructured
semiconductor &
contacts
release in water
the entire device stack peels back, now
fully transferred to the flexible polyimide.
After a few additional fabrication
steps, the results are flexible transistors
capable of several times higher performance
than any produced before with
atomically thin semiconductors. While
entire circuits could be built and then
transferred to the flexible material, certain
complications with subsequent layers
make these additional steps easier
after transfer.
Illustration of the transfer process for a 2D semiconductor with nanopatterned contacts (left) and
a photograph of the flexible transparent substrate with transferred structures (right). (Image:
Victoria Chen/Alwin Daus/Pop Lab)
lution otherwise impossible on flexible
plastic substrates.
The layering technique, known as
chemical vapor deposition (CVD), grows
a film of MoS2 one layer of atoms at a
time. The resulting film is just three atoms
thick but requires temperatures reaching
850 °C (over 1500 °F) to work. By comparison,
the flexible substrate - made of
polyimide, a thin plastic - would long
ago have lost its shape somewhere around
360 °C (680 °F) and completely decomposed
at higher temperatures.
By first patterning and forming these
critical parts on rigid silicon and allowing
them to cool, the researchers can apply
the flexible material without damage.
With a simple bath in deionized water,
Glass Injection Molding
The process produces rapid, cost-effective, and environmentally friendly material.
University of Freiburg, Germany
S
haping glass is mainly based on
processes such as melting, grinding,
or etching. These processes are decades
old, technologically demanding, energyintensive,
and severely limited in terms of
the shapes that can be realized. Re -
searchers have developed a process that
makes it possible to form glass easily,
quickly, and in almost any shape using
injection molding. The process combines
polymer and glass processing, effectively
replacing both mass-produced products
and complex polymer structures and
components with glass.
Injection molding is the most important
process in the plastics industry and
enables the fast and cost-effective production
of components in almost any shape
and size. Transparent glass previously
could not be molded using this process.
With the new " Glassomer " injection molding
technology from a special granulate, it
is now possible to mold glass in high
throughput at 130 °C. The injection-mold40
Cov
The
devices can handle high electrical
currents while operating at low voltage,
as required for low power consumption.
Meanwhile, the gold metal
contacts dissipate and spread the heat
generated by the transistors while in use
- heat that might otherwise jeopardize
the flexible polyimide.
The team is looking into integrating
radio circuitry with the devices, which
will allow future variations to communicate
wirelessly with the outside world -
another step toward viability for flextronics,
particularly those implanted in
the human body or integrated deep
within other devices.
For more information, contact Taylor
Kubota at tkubota@stanford.edu.
Injection-molded structures made from the Glassomer composite. (Photo: NeptunLab/University
of Freiburg)
ed components are then converted into
glass in a heat treatment process - the
result is pure quartz glass. The process
requires less energy than conventional
glass melting, resulting in energy efficiency.
The formed glass components have a
high surface quality, so that post-treatment
steps such as polishing are not required.
www.techbriefs.com
ToC
The designs made possible by Glass -
omer's glass injection molding technology
have a range of applications, from
data technology and solar technology, to
lab-on-a-chip and medical technology. In
addition to transparency, the very low
coefficient of expansion of quartz glass
also makes the technology suited for senTech
Briefs, October 2021
rigid substrate
flexible polyimide

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Tech Briefs Magazine - October 2021

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