Researchers at Princeton University have developed an extremely thin semiconductor that can have its electronic properties programmed, erased and programmed again using light.
The discovery could eventually lead to smarter and more energy-efficient computers, sensors and other electronic devices.
Semiconductors are at the heart of modern electronics, powering everything from computers and televisions to smartphones and household appliances.
For decades, improvements in computing have largely depended on making semiconductor components smaller so that more of them can fit onto a single chip.
But this strategy is approaching physical limits. Electronic components have become so tiny that continuing to shrink them is increasingly difficult.
Instead of simply making existing technology smaller, researchers are exploring new materials that can perform functions conventional semiconductors cannot.
The Princeton team is taking this approach by creating a semiconductor that can change how it behaves after it has already been manufactured.
“One of the future goals for advancing electronics is not just making materials smaller, but making them adaptable and smarter,” said Jaehoon Ji, a postdoctoral researcher and first author of the study, published in Science Advances.
Traditional semiconductor devices respond to electrical signals, but their basic electrical properties are largely determined when they are manufactured. The new material is different because its behavior can be modified repeatedly.
To achieve this, the researchers combined an ultra-thin semiconductor, only a few molecules thick, with molecules that respond to light. When exposed to different wavelengths of light, these molecules change their structure.
Those structural changes then affect the semiconductor, altering both how it conducts electricity and how it responds to light. As a result, researchers can use light to program the material’s properties and later erase or change those settings.
The technology is more sophisticated than a simple switch that moves between “on” and “off.” Instead, the researchers can gradually adjust the semiconductor’s response to different levels and then reverse those changes.
That ability could eventually allow electronic devices to adapt their behavior depending on what they are being used for, rather than being permanently designed to perform one fixed function.
The researchers were inspired partly by biological systems, which constantly detect changes in their surroundings and adjust their behavior in response.
“Living systems are extremely smart, because they continuously sense and respond to their surroundings,” said Saien Xie, assistant professor of electrical and computer engineering and senior author of the study. The team wanted to bring some of that adaptability to electronic materials.
The researchers have already produced a uniform sheet of the ultra-thin semiconductor measuring about one inch square. They have also used the material to create arrays of programmable electronic switches.
Their next goal is to connect these switches into a working circuit, an essential step toward developing more complicated electronic systems.
In the longer term, the researchers envision electronics whose capabilities are not permanently determined during manufacturing. Instead, devices could potentially be reconfigured after they have been built, allowing the same hardware to perform different tasks as needed.
Such adaptable materials could ultimately open new possibilities for computing, sensing and optoelectronic technologies while helping engineers move beyond the limits of simply making today’s semiconductor devices smaller.
