Can Ferroelectric Semiconductors Bring Us Closer to Batteryless IoT Devices?

Engineers, researchers, tech entrepreneurs, and others are increasingly interested in the Internet of Things (IoT) products that can work without batteries. Some achievements in this area include innovations that can get power from their surrounding environments, such as soaking up sunlight or harnessing the kinetic energy from people’s movements. However, recent work also indicates that a ferroelectric semiconductor could create progress for improved IoT and artificial intelligence (AI) applications.

What Is a Ferroelectric Semiconductor?

When a material has ferroelectric properties, it can show a spontaneous electric polarization that someone can reverse through external exposure to an electric field, changing which end has a positive or negative charge.

A ferroelectric semiconductor fits that description while also having the electronic bandgap aspects of conventional semiconductors. Researchers working on ferroelectric semiconductor applications believe they could develop new IoT sensors, memory devices, and more. 

Nanoscale Ferroelectric Semiconductors

Researchers from the University of Michigan made significant progress that could shape future ferroelectric semiconductor applications. They designed ferroelectric semiconductors that are only 5 nanometers thick, or the width of approximately 50 atoms.

The team believed their work could produce more ferroelectric technologies in small, everyday devices, such as smartphones. The group was particularly interested in how their work could upgrade legacy products and give them next-generation capabilities.

Zetian Mi, a professor of electrical and computer engineering and the co-corresponding author of the study, envisioned a future where people could use mainstream semiconductors that fully integrate with extremely efficient, ultra-low-power devices.

More specifically, the ferroelectric nature of the semiconductors allows people to switch their polarization. Future work might involve using that aspect to sense acoustic vibrations or light. Even more importantly, it could enable people to build IoT devices that harvest ambient energy and become self-powered. 

Future ferroelectric semiconductor applications could also store and process traditional and quantum information, such as if the two electrical polarization states act as ones and zeros called binary digits.

Alternatively, the polarization could emulate the human brain’s connections between neurons that allow people to remember things and process information. Work in that area happens in the realm known as neuromorphic computing. Individuals specializing in it develop the architectures related to AI algorithms that use neural networks to function. 

Necessary Innovation for Tech Advancement

Engineers and manufacturers continually develop and produce improved semiconductors. For example, some high-end applications demand chips made with thermoset plastics.

They’re more expensive than other materials but offer excellent chemical resistance and strength, making them suitable for particular needs.

Similar to how people have investigated practical ways to enhance semiconductors, they’ve explored alternative energy sources for IoT devices. That’s especially necessary as people increasingly deploy connected devices in remote or hard-to-reach areas.

IoT sensors can alert people in the oil and gas industry to potential leaks or make them aware of faults in a city’s water infrastructure. However, changing or replacing the batteries in such IoT applications is not always easy.

That’s one of the main reasons researchers are looking at ferroelectric semiconductors and beyond to find potential options that reduce or eliminate batteries as power sources. 

In one 2022 case, researchers developed a wireless IoT device that harvested vibrational energy. That invention could detect the coronavirus and transmit information about contaminated environments without relying on an external power source. 

Going back to the University of Michigan's achievement, the researchers are particularly excited about using electrical polarization as an energy storage mechanism. They believe this approach would be less power-intensive than using the capacitors in random access memory (RAM). Those must constantly use power to avoid losing stored data. 

Additionally, the research team thought their ferroelectric semiconductors could require less energy than solid-state drives (SSD) and have comparatively more capacity due to dense energy storage.

Another characteristic that lends itself well to IoT devices is that these semiconductors could show better resistance to demanding environments, including those featuring radiation, high humidity, and temperature extremes. 

Relying on Earlier Work

This is not the first time Mi and his research team have studied ferroelectric semiconductors. Earlier work involved creating an aluminum-nitride semiconductor and spiking it with a metal called scandium, which people sometimes use to strengthen aluminum in applications such as fighter jets and high-performance bicycles.

However, a downside of that previous achievement was that the material was too thick for many contemporary applications.

Then, in 2021, the group successfully demonstrated their ability to tune the electrical polarity of a semiconductor. At that time, they were particularly excited by how ferroelectric technologies could improve everything from the 5G network to biological research. 

However, they knew that their innovations would be more applicable to modern computing and advanced devices if they could make semiconductors with films less than 10 nanometers thick.

They did this most recently using molecular beam epitaxy, which people previously used to make the semiconductor crystals associated with CD and DVD player lasers. 

That work allowed making a semiconductor crystal only 5 nanometers thick — which was the smallest scale yet. Their method required controlling each layer of atoms in the ferroelectric semiconductor and restricting atom loss from the surface. 

The results associated with the reduced thickness made the researchers confident that they could reduce the operation voltage. If that’s true, ferroelectric semiconductors would enable the development of smaller IoT devices that need less power while running.

This manufacturing work at the nanoscale level also helps scientists identify the semiconductor material’s primary properties and any limitations it might have. The group might then use those takeaways to further work related to quantum systems and devices.

Removing Battery-Free Barriers

It’s easy to see the advantages of IoT devices that don’t need batteries. Once the technology becomes more widespread, it could result in products that are more user-friendly and cheaper to manufacture than the options available now. 

Alternatively, this ferroelectric semiconductor could pave the way for innovations that are impossible or highly impractical now because of known technological limitations. Even if researchers eventually identify issues that make their inventions less scalable than they thought, this collective work is instrumental in pushing science and technology forward.

Work in this area will prove invaluable to teams interested in developing ferroelectric semiconductors for various applications, including those involving IoT devices.