Zuzanna Szybisty, a master’s student in Electrical Engineering at UT, is trying to make one of the world’s most important materials emit light.
We all use silicon. It is the key ingredient in computer chips, powering our phones, laptops, and internet servers. But there is one thing it does not do well: emitting light. “If we can teach silicon to emit light, we could make computer chips that are faster, more efficient, and more powerful.” Her research may sound technical (and it is), but the impact could one day extend to everything from cloud computing to medical data to quantum technology.
But why should silicon emit light?
We already have LEDs; the lights in our TVs, headlights, and Christmas decorations. But they are not made of silicon. They are built from special materials that are great at producing light, but not very compatible with electronics. The challenge is that silicon, our go-to material for electronics, is not naturally good at shining. It is a bit like trying to make a brick sing. You can try, but that is just not what bricks (or silicon) are built for.
Light signals could replace electricity to carry information inside your devices, thus making them faster and more energy-efficient. “The aim is to increase emission efficiency. The issue with silicon LEDs is that, in general, they are not efficient enough to make large-scale production profitable,” Zuzanna says.
A different silicon LED
The little devices Zuzanna works on are called silicon LEDs. These are light-emitting diodes made of silicon. But hers are far from ordinary. They are built on a film of silicon that is less than 10 nanometres thick. That is about 10,000 times thinner than a human hair. “These LEDs are precision instruments with additional contacts or terminals (3 to 4 in diodes, instead of 2) and even a photo-detector,” she says. So they can both emit and detect light, kind of like a walkie-talkie, but for photons.
The light emitted by these LEDs is not what researchers expected. Normally, silicon emits light at one specific colour: infrared, around 1120 nanometers, which is invisible to the human eye. But Zuzanna’s LEDs produce a much wider range of light, from 1080 all the way to 1600 nanometres. “We are not totally sure why. It could be because the silicon is so thin, or because of how the layers in the device reflect light.”
This broader spectrum is exciting because it includes the exact type of light used in telecommunications. It is the same light that travels through fibre-optic cables to carry your YouTube videos or Teams calls.
Measuring light
Zuzanna measures these tiny light sources in terms of their behaviour, both electrically and optically. That means she looks at how much current flows through them and what kind of light they emit. “Sometimes it takes 20 minutes to record one light spectrum,” she says. “But the device is so delicate, it might overheat before the measurement finishes.”
To avoid building dozens of test versions, she also uses simulation software, like a digital lab where she can tweak the design and instantly see the results.
The big picture
These experiments are still in their early stages, but they could one day contribute to more efficient and versatile computer chips. Instead of relying solely on electrical signals, future devices might use light to transfer data, thus making higher data throughput and lower energy consumption possible. “It is still fundamental research,” Zuzanna says, “but by understanding how these silicon-based devices emit and interact with light, we can explore entirely new ways to integrate photonics with existing chip technology.”
The long-term goal is to improve how efficiently silicon emits light, making sure it operates in the telecommunications wavelength range, and potentially combine emission and detection in a single device (like an optocoupler made from just silicon). While challenges remain, especially around boosting emission efficiency, every insight from these prototypes helps move toward scalable, silicon-compatible solutions for optical data communication and sensing.
Between physics and engineering
Zuzanna is combining two specialisations (semiconductor devices and integrated optics) in a way few master’s students attempt. “I love engineering that is close to physics. Where you are not just building things, but figuring out how they really work.” She has already made up her mind: she wants to pursue a PhD after her master’s and stay in research. “Being in this environment, surrounded by curious people, constantly exploring new ideas, that is where I want to be.”
Before these silicon LEDs can show up in real-world tech, there is still a lot to figure out. “We are learning something new about silicon.” So can silicon learn to shine? With researchers like Zuzanna working on it, the answer might one day be yes.
