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Researchers give 2D electronics a performance boost

Singaporean researchers give 2D electronics a performance boost

Creating ripples in 2D material, molybdenum disulfide, was found to increase the mobility of carriers at room temperature by two orders, allowing electrons to move faster through the material. Credit: A*STAR’s Institute of Materials Research and Engineering

Two-dimensional (2D) semiconductors have a unique property that allows their thickness to be reduced to one or a few atoms. transistor prematurely.

Despite the potential that 2D semiconductors have to replace conventional semiconductor materials such as silicon in the future, a major challenge remains: their low carrier mobility at room temperature, caused by strong scattering between electrons and phonons.

Road and traffic conditions determine the amount of time and energy a person spends traveling from one location to another. Similarly, carrier mobility measures how fast a carrier, such as an electron or a hole, can move through a material when there is an electric field. This property also determines whether a semiconductor material is suitable for electronic devices.

High carrier mobility can effectively reduce the power dissipation in integrated circuits and lower the overall power consumption, thereby extending the life of electrical devices or systems and reducing the cost of operating these devices or systems.

Researchers from the Agency for Science, Technology and Research (A*STAR) Institute of Materials Research and Engineering (IMRE), Fudan University, National University of Singapore and The Hong Kong Polytechnic University recently discovered that placing 2D materials on substrates with bulging morphologies can improve the mobility of carriers at room temperature by two orders. These bulges create ripples in the material, distorting the lattice structure — moving one or more atoms from their original position in an ideal structure.

This approach contrasts with conventional strategies that rely on perfect lattice structures to improve carrier mobility, as any impurity or lattice distortion is believed to adversely affect mobility.

In a study published in Nature Electronics in June 2022, researchers saw that corrugated 2D molybdenum disulfide (MoS2) with lattice distortions create greater electrical polarization that can renormalize the frequency of phonons. This renormalized phonon frequency effectively reduces the strength of scattering between electrons and phonons, increasing the mobility of carriers in MoS2. This means that electrons can now move faster through the material.

Study results show that the mobility of carriers at room temperature is improved by two orders in corrugated MoS2up to about 900 cm2 V-1 s-1. The observed result exceeds the predicted phonon-constrained carrier mobility of flat MoS2 from 200–410 cm2 V-1 s-1.

Through the study, creating bulges in the lattice structure of MoS2 was found to overcome the intrinsic carrier mobility limit of the material. This clears the way for MoS2 and other 2D materials that can be used in making field effect transistors and thermoelectric devices with competitive room temperature performance.

“Our approach is simple and cost-effective, demonstrating lattice engineering as an effective strategy to create high-performance room temperature electronics and thermoelectric devices for future electronics,” said Dr. Wu Jing, scientist at A*STAR’s IMRE.

“We further reveal the underlying mechanism that the enhanced carrier mobility is due to the suppressed electron-phonon scattering and the increased intrinsic dielectric constant caused by the corrugated structures in the 2D semiconductor. Both play synergistic effects to enhance the intrinsic mobility. of the wearer.” said Dr. Yang Ming, assistant professor in the Department of Applied Physics, Hong Kong Polytechnic University.

Using lattice distortions to improve carrier mobility in 2D semiconductors

More information:
Hong Kuan Ng et al, Improving the mobility of carriers in two-dimensional semiconductors with corrugated materials, Nature Electronics (2022). DOI: 10.1038/s41928-022-00777-z

Provided by Agency for Science, Technology and Research (A*STAR), Singapore

Quote: Researchers give 2D electronics a performance boost (2022, July 27) retrieved July 27, 2022 from https://phys.org/news/2022-07-2d-electronics-boost.html

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