Scientists Design a WS2-Based Stack to Reduce Computing Power Consumption

Scientists have recently designed a WS2-based multi-stacked structure based on 2D materials. By comprising a tungsten disulfide (WS₂) layer in hexagonal boron nitride (hBN) layers, the continuous WS₂ layer displays long-range interaction between successive WS₂ layers with the potential for reducing circuit design complexity and computing power consumption.

Due to their lucrative electronic properties, two-dimensional materials have been popular among photovoltaic, semiconductor, and water purification fields, and are favored by material scientists. In particular, the relative physical and chemical stability of two-dimensional materials allows them to "stacked" and "integrate" with each other.

This stability of two-dimensional materials makes it possible to fabricate structures based on two-dimensional materials, such as coupled "quantum wells" (CQWs), a system of interacting potential wells, or regions holding very little energy, which allow only specific energies for the particles trapped within them.

CQWs can be used to design resonant tunnel diodes. This electronic device exhibits a negative rate of voltage change with current and is an important part of integrated circuits. Such chips and circuits are integral in technologies that emulate neurons and synapses responsible for the biological brain’s memory storage.

A research team led by Dr. Myoung-Jae Lee from Daegu Gyeongbuk Institute of Science and Technology (DGIST) designed a CQW system that stacks a tungsten disulfide layer between two hexagonal boron nitride (hBN) layers. Dr. Lee said: "hBN is an almost ideal two-dimensional insulator with high chemical stability. This makes it a perfect choice for WS₂-based integration, which is a known 2D form of semiconductor." The results are published in ACS Nano.

The research team measured the energy of the excitons-bound system and compared it with the bilayer WS₂ architecture. The system integrates electrons, electron holes (absence of electron), and trions for CQW. In addition, they also measured the current-voltage characteristics of a single CQW to describe its behavior.

As the stakes increase, exciton and trion will gradually decrease, while bilayer WS₂-based bilayer will decrease abruptly. They attributed these observations to the long-range inter-well interaction and the strong interaction of WS₂ - WS₂ in the absence of hBN. The current-voltage characteristics confirm that it behaves like a resonant tunnel diode.

So, what impact will these results have on the future of electronics? Professor Lee concluded: "We can use resonant tunnel diodes to make multi-valued logic devices, which will greatly reduce circuit complexity and computing power consumption. This, in turn can drive the development of low-power electronic products."

These discoveries of WS₂-based stacks will bring revolutionary changes to the electronics industry with extremely low-power semiconductor chips and circuits, but what is even more exciting is where these chips can take us, because they can be used to mimic neurons and the application of synapses, which play an important role in the memory storage of biological brains. Therefore, this "two-dimensional perspective" may be the next big thing in the field of artificial intelligence.

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