Levitating 2-D semiconductors for better performance

August 28, 2018, The Korea Advanced Institute of Science and Technology (KAIST)
Figure 1. Image of a 2D semiconductor using dome structures. Credit: The Korea Advanced Institute of Science and Technology (KAIST)

Atomically thin 2-D semiconductors have been drawing attention for their superior physical properties over silicon semiconductors; nevertheless, they are not the most appealing materials due to their structural instability and costly manufacturing process. To shed some light on these limitations, a KAIST research team suspended a 2-D semiconductor on a dome-shaped nanostructure to produce a highly efficient semiconductor at a low cost.

2-D semiconducting materials have emerged as alternatives for silicon-based semiconductors because of their inherent flexibility, high transparency, and excellent carrier transport properties, which are the important characteristics for flexible electronics.

Despite their outstanding physical and chemical properties, they are oversensitive to their environment due to their extremely thin nature. Hence, any irregularities in the supporting surface can affect the properties of 2-D semiconductors and make it more difficult to produce reliable and well performing devices. In particular, it can result in serious degradation of charge-carrier mobility or light-emission yield.

To solve this problem, there have been continued efforts to fundamentally block the substrate effects. One way is to suspend a 2-D ; however, this method will degrade mechanical durability due to the absence of a supporter underneath the 2-D semiconducting materials.

Professor Yeon Sik Jung from the Department of Materials Science and Engineering and his team came up with a new strategy based on the insertion of high-density topographic patterns as a nanogap-containing supporter between 2-D materials and the substrate in order to mitigate their contact and to block the substrate-induced unwanted effects.

More than 90% of the dome-shaped supporter is simply an empty space because of its nanometer scale size. Placing a 2-D semiconductor on this structure creates a similar effect to levitating the layer. Hence, this method secures the mechanical durability of the device while minimizing the undesired effects from the substrate. By applying this method to the 2-D semiconductor, the charge-carrier mobility was more than doubled, showing a significant improvement of the performance of the 2-D semiconductor.

Additionally, the team reduced the price of manufacturing the semiconductor. In general, constructing an ultra-fine dome structure on a surface generally involves costly equipment to create individual patterns on the surface. However, the team employed a method of self-assembling nanopatterns in which molecules assemble themselves to form a nanostructure. This method led to reducing production costs and showed good compatibility with conventional semiconductor manufacturing processes.

Professor Jung said, "This research can be applied to improve devices using various 2-D semiconducting materials as well as devices using graphene, a metallic 2-D material. It will be useful in a broad range of applications, such as the material for the high speed transistor channels for next-generation flexible displays or for the active layer in light detectors."

Explore further: Designing a 'solar tarp,' a foldable, packable way to generate power from the sun

More information: Soonmin Yim et al. Nanopatterned High-Frequency Supporting Structures Stably Eliminate Substrate Effects Imposed on Two-Dimensional Semiconductors, Nano Letters (2018). DOI: 10.1021/acs.nanolett.8b00084

Related Stories

Stretching to perfection of 2-D semiconductors

November 15, 2017

Compressing a semiconductor to bring atoms closer together or stretching it to move them farther apart can dramatically change how electricity flows and how light is emitted. Scientists found an innovative way to compress ...

Eco-friendly waterborne semiconductor inks using surfactant

November 28, 2017

A research team of Energy Science and Engineering at DGIST has developed a technology to produce environmentally friendly water-borne semiconductor inks using surfactants, additives that mix substances of different properties ...

Team engineers oxide semiconductor just single atom thick

February 8, 2017

A new study, affiliated with UNIST has introduced a novel method for fabrication of world's thinnest oxide semiconductor that is just one atom thick. This may open up new possibilities for thin, transparent, and flexible ...

High-speed and on-silicon-chip graphene blackbody emitters

April 4, 2018

High-speed light emitters integrated on silicon chips can enable novel architectures for silicon-based optoelectronics. However, compound-semiconductor-based light emitters face major challenges for their integration with ...

Recommended for you

Coffee-based colloids for direct solar absorption

March 22, 2019

Solar energy is one of the most promising resources to help reduce fossil fuel consumption and mitigate greenhouse gas emissions to power a sustainable future. Devices presently in use to convert solar energy into thermal ...

Paleontologists report world's biggest Tyrannosaurus rex

March 22, 2019

University of Alberta paleontologists have just reported the world's biggest Tyrannosaurus rex and the largest dinosaur skeleton ever found in Canada. The 13-metre-long T. rex, nicknamed "Scotty," lived in prehistoric Saskatchewan ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.