HomeNewsNanotechnologyNew atomically skinny materials might enhance effectivity of light-based tech

New atomically skinny materials might enhance effectivity of light-based tech


So-called “two-dimensional” supplies have distinctive electrical and photonic properties, however their ultra-thin type elements current sensible challenges when included into gadgets. Penn Engineering researchers have now demonstrated a technique for making large-area “superlattices” — layered constructions containing 2D lattices of sulfur and tungsten — that may obtain light-matter coupling. Credit: University of Pennsylvania

Solar panels, cameras, biosensors and fiber optics are applied sciences that depend on photodetectors, or sensors that convert mild into electrical energy. Photodetectors have gotten extra environment friendly and reasonably priced, with their part semiconductor chips lowering in dimension. However, this miniaturization is pushing in opposition to limits set by present supplies and manufacturing strategies, forcing trade-offs between dimension and efficiency.


Solar panels, cameras, biosensors and are applied sciences that depend on photodetectors, or sensors that convert mild into electrical energy. Photodetectors have gotten extra environment friendly and reasonably priced, with their part semiconductor chips lowering in dimension. However, this miniaturization is pushing in opposition to limits set by present supplies and manufacturing strategies, forcing trade-offs between dimension and efficiency.

There are many limitations of the normal semiconductor chip manufacturing course of. The chips are created by rising the semiconductor movie excessive of a wafer in a method the place the movie’s crystalline construction is in alignment with that of the substrate wafer. This makes it troublesome to switch the movie to different substrate supplies, lowering its applicability.

Additionally, the present methodology of transferring and stacking these movies is finished by way of mechanical exfoliation, a course of the place a chunk of tape pulls off the semiconductor movie after which transfers it to a brand new substrate, layer by layer. This course of ends in a number of non-uniform layers stacked upon each other with every layer’s imperfections amassed in the entire. This course of impacts the standard of the product in addition to limits the reproducibility and scalability of those chips.

Lastly, sure supplies don’t perform nicely as extraordinarily skinny layers. Silicon stays ubiquitous as the fabric of alternative for semiconductor chips, nevertheless, the thinner it will get, the more severe it performs as a photonic construction, making it lower than best in photodetectors. Other supplies that carry out higher than silicon as extraordinarily skinny layers nonetheless require a sure thickness to work together with mild, posing the problem of figuring out optimum photonic supplies and their vital thickness to function in photodetector semiconductor chips.

Manufacturing uniform, extraordinarily skinny, prime quality photonic semiconductor movies of fabric aside from silicon would make semiconductor chips extra environment friendly, relevant, and scalable.

Penn Engineers Deep Jariwala, Assistant Professor in Electrical and Systems Engineering, and Pawan Kumar and Jason Lynch, a postdoctoral fellow and a doctoral scholar in his lab, led a examine printed in Nature Nanotechnology that aimed to do exactly that. Eric Stach, Professor in Materials Science and Engineering, alongside together with his postdoc Surendra Anantharaman, doctoral scholar Huiqin Zhang and undergraduate scholar Francisco Barrera additionally contributed to this work. The collaborative examine additionally included researchers at Penn State, AIXTRON, UCLA, the Air Force Research Lab and the Brookhaven National Lab, and was primarily funded by the Army Research Lab. Their paper describes a brand new methodology of producing atomically skinny superlattices, or semiconductor movies, which can be extremely mild emissive.

One-atom-thick supplies usually take the type of a lattice, or a layer of geometrically aligned atoms that type a sample particular to every materials. A is made up of lattices of various supplies stacked upon each other. Superlattices have utterly new optical, chemical and bodily properties that make them adaptable for particular functions equivalent to picture optics and different sensors.

The workforce at Penn Engineering made a superlattice, 5 atoms thick, of tungsten and sulfur (WS2).

“After two years of research using simulations that informed us how the superlattice would interact with the environment, we were ready to experimentally build the superlattice,” says Kumar. “Because traditional superlattices are grown on a desired substrate directly, they tend to be millions of atoms thick, and difficult to transfer to other material substrates. We collaborated with industry partners to ensure that our atomically thin superlattices were grown to be scalable and applicable to many different materials.”

They grew monolayers of atoms, or lattices, on a two-inch wafer after which dissolved the substrate, which permits the lattice to be transferred to any desired materials, of their case, sapphire. Additionally, their lattice was created with repeating models of atoms aligned in a single route to make the superlattice two-dimensional, compact and environment friendly.

“Our design is scalable as well,” says Lynch. “We were able to create a superlattice with a surface area measured in centimeters with our method, which is a major improvement compared to the micron scale of silicon superlattices currently being produced. This scalability is possible due to uniform thickness in our superlattices, which makes the manufacturing process simple and repeatable. Scalability is important to be able to place our superlattices on the industry-standard, four-inch chips.”

Their superlattice design just isn’t solely extraordinarily skinny, making it light-weight and value efficient, it may well additionally emit mild, not simply detect it.

“We are using a new type of structure in our superlattices that involves exciton-polaritons, which are quasi-state particles made of half matter and half light,” says Lynch. “Light is very hard to control, but we can control matter, and we found that by manipulating the shape of the superlattice, we could indirectly control light emitted from it. This means our superlattice can be a light source. This technology has the potential to significantly improve lidar systems in self-driving cars, facial recognition and computer vision.”

Being in a position to each emit and detect mild with the identical materials opens the door for extra sophisticated functions.

“One current technology that I can see our superlattice being used for is in integrated photonic computer chips which are powered by light,” says Lynch. “Light moves faster than electrons, so a chip powered by light will increase computing speed, making the process more efficient, but the challenge has been finding a supply that may energy the . Our superlattice could also be an answer there.”

Applications for this new expertise are various and can possible embody high-tech robotics, rockets and lasers. Because of the big selection of functions for these superlattices, the scalability is essential.

“Our superlattices are made with a general, non-sophisticated process that does not require multiple steps in a clean room, allowing the process to be repeated easily,” says Kumar. “Additionally, the design is applicable to many different types of materials, allowing for adaptability.”

“In the tech world, there is a constant evolution of things moving toward the nanoscale,” he says. “We will definitely be seeing a thinning down of microchips and the structures that make them, and our work in the two-dimensional material is part of this evolution.”

“Of course, as we thin things down and make technology smaller and smaller, we start to interact with quantum mechanics and that’s when we see interesting and unexpected phenomena occur,” says Lynch. “I’m very excited to be part of a workforce bringing into high-impact expertise.”


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More data:
Pawan Kumar et al, Light–matter coupling in large-area van der Waals superlattices, Nature Nanotechnology (2021). DOI: 10.1038/s41565-021-01023-x

Citation:
New atomically skinny materials might enhance effectivity of light-based tech (2021, December 21)
retrieved 21 December 2021
from https://phys.org/news/2021-12-atomically-thin-material-efficiency-light-based.html

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