Carbon film with crazy electron spin life could boost quantum devices production

Australia-based semiconductor company Archer Materials has developed an advanced carbon film that can boost the production of quantum materials. The electron spin of these films lasts for 400 nanoseconds — far longer than the lifetimes previously observed in carbon nano-onions.

“The new carbon films can be processed into quantum devices using standard semiconductor fabrication techniques, overcoming the manufacturing roadblock for carbon nano-onions,” the Archer Materials team notes.

Carbon nano-onions (CNOs) are nanometer-scale structures made up of multiple carbon layers. Since they offer excellent electrical conductivity and can keep electron spins stable for extended periods, they are important for the creation of qubits and the development of faster electronic components.

However, manufacturing CNOs on a large scale has been challenging. This is also one of the reasons why quantum devices are not yet widely available.

The researchers from Archer Materials suggest that their newly developed carbon films can make CNO production scalable. Plus, it can be used alongside CNOs to speed up quantum material manufacturing.

A carbon film for quantum devices

The researchers developed a proprietary chemical vapor deposition process, which enabled them to deposit the carbon film on substrates such as silicon without any difficulties.

They suggest that this “process is extremely clean, ensuring films have extremely low or controlled levels of impurities and contaminants,” — resulting in the production of wafers with lifespans reaching 400 ns.

Interestingly, as mentioned above, the carbon films are produced using a simple method. On the other hand, the production of CNOs is quite complex and challenging, often resulting in high levels of impurities.

However, when the researchers further studied the carbon film using electron microscopy , they discovered that the internal structure of the film shares similarities with that of CNOs. This suggests that the carbon films could reveal ways to scale up the production of CNOs.

“Manufacturability of many quantum materials is an ongoing challenge in the field. Working on this new film, alongside CNOs or even in place of CNOs, will accelerate the development of our quantum technology and provide a means of volume manufacturing of such devices,” Greg English, executive chair of Archer, stated.

Moreover, “The electron spin properties combined with the manufacturability opens a path to using the carbon material in a wide variety of applications like extremely sensitive magnetometers or the biotechnology field, in addition to quantum computing,” the researchers added.

Next step: Make the carbon film quantum-ready

The carbon film has properties that seem promising for the development of quantum materials but before it is deployed, it is important to understand the factors that provide it with such an impressive spin lifetime.

This is what the researchers are planning to do next. “Work is in progress to understand the key parameters that impact spin lifetime so that the material can be further tuned for quantum performance,” they said.

To show how the carbon film could be used, the researchers created and grew a cross-section view of the film on a silicon substrate. They shaped this film into an array of nanoscale islands.

“Devices can then be fabricated around these islands using conventional semiconductor fabrication processes. Such a structure could be the basis for scaling qubits or building a sensing array on chip,” the Archer Materials team added.

Nothing close to such a practical application has ever been achieved with CNOs to date. This innovation has the potential to accelerate the development of feasible quantum devices .