A team of researchers led by Professor Yong-Young Noh and Dr. Youjin Reo from POSTECH (Pohang University of Science and Technology) has developed a groundbreaking technology that could revolutionize the way we use electronic devices.
Working alongside Professors Ao Liu and Huihui Zhu from the University of Electronic Science and
Technology of China (UESTC), the team discovered a way to create powerful, efficient semiconductor layers using a method called thermal evaporation.
Their findings were published in Nature Electronics.
When you stream videos, play games, or scroll through social media on your smartphone, thousands of tiny components called transistors are at work.
These transistors act like traffic lights for electricity, controlling the flow of electric current to make sure everything runs smoothly.
Typically, transistors are divided into two types: n-type, which move electrons, and p-type, which move “holes,” or spaces where electrons aren’t. Until now, n-type transistors have always been faster and more efficient than p-type ones, which has limited how powerful our devices can be.
To solve this, the researchers focused on a special material called tin-based perovskite, which has a unique crystal structure that makes it perfect for high-performance p-type transistors.
Traditionally, this material could only be made through a process similar to soaking ink into paper, which is not ideal for large-scale manufacturing because it’s hard to control the quality.
In a significant breakthrough, the team applied a manufacturing method called thermal evaporation, which is already widely used for making OLED TVs and semiconductor chips.
This technique involves heating materials until they turn into vapor, then letting them settle onto surfaces to form thin, even layers. By using this method, they were able to create high-quality layers of a material called cesium-tin-iodide (CsSnI3).
To make the material even better, they added a small amount of lead chloride (PbCl2), which improved the smoothness and quality of the thin films.
The transistors made from these films showed impressive performance, with a speed (mobility) of over 30 cm²/V·s and an on/off current ratio of 10⁸, which is comparable to commercial n-type semiconductors. This means the new p-type transistors are not only faster but also consume less power.
This innovation solves two big problems: it boosts the stability of the devices and allows for the creation of large-area circuits, something that was not possible with older methods. Even better, the technology fits right into the equipment already used for making OLED displays, making it cheaper and easier to produce.
Professor Yong-Young Noh explained that this new technology could pave the way for ultra-thin, flexible, and high-resolution screens for smartphones, TVs, and even wearable electronics, thanks to its low processing temperature of under 300°C.
This breakthrough could be the key to next-generation electronic devices that are faster, more efficient, and easier to manufacture.
