Scientists create 'armour' for quantum technology

Researchers at the ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET) have led the development of so-called ‘body armour’ for extremely fragile quantum systems, which will make them robust enough to be used as the basis for a new generation of low-energy electronics. Their work has been published in the journal Advanced Materials.

Serving as lead author on the study was Matthias Wurdack, a PhD student at the Australian National University (ANU) and FLEET. He explained that protection is crucial for thin materials such as graphene, which are only a single atom thick — essentially two-dimensional — and so are easily damaged by conventional layering technology.

With this in mind, the team created a protective layer by exposing to air a droplet of liquid gallium, which immediately formed a perfectly even layer of gallium oxide on its surface just 3 nm thick. By squashing the droplet on top of the 2D material with a glass slide, the gallium oxide layer can be transferred from the liquid gallium onto the material’s entire surface, up to centimetres in scale.

“The protective coating basically works like a body armour for the atomically thin material; it shields against high-energy particles, which would cause a large degree of harm to it, while fully maintaining its optoelectronic properties and its functionality,” Wurdack said.

Because this ultrathin gallium oxide is an insulating amorphous glass, it conserves the optoelectronic properties of the underlying 2D semiconductor. The gallium oxide glass can also enhance these properties at cryogenic temperatures and protects well against other materials deposited on top. This allows the fabrication of sophisticated, layered nanoscale electronic and optical devices, such as light emitting diodes, lasers and transistors.

“We’ve generated a nice alternative to existing technology that can be scaled for industry applications,” Wurdack said.

The work also promises lower-energy alternatives for electronics and optoelectronics, by harnessing the superior performance of 2D semiconducting materials such as tungsten disulfide, which was used in this study. As explained by team leader Professor Elena Ostrovskaya, also from ANU and FLEET, “Two-dimensional materials have extraordinary properties, such as extremely low resistance or highly efficient interactions with light.

“Because of these properties, they could have a big role in the fight against climate change.”

Using 2D materials to make more efficient devices will have advantages beyond reduced carbon emissions, with Wurdack saying, “2D technology could also enable super-efficient sensors on spacecraft or processors in Internet of Things devices that are less limited by battery life.”

Wurdack said he and his team “hope to find industry partners to work with us to develop a protective layer printer based on this technology that can go into any lab, like a lithography machine”.

“It would be exciting to see fundamental research like this find its way into industry,” he said.

Image caption: FLEET PhD student Matthias Wurdack. Image credit: Phil Dooley, ANU.

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