A South Korean research team has achieved a breakthrough in semiconductor technology, successfully developing a p-type perovskite transistor with significantly enhanced performance and stability. This advancement is expected to address a core challenge that has long constrained the development of high-performance, low-power chips and open new pathways for next-generation memory devices like vertically stacked DRAM for AI computing.
According to a Thursday report, a research team led by Professor Noh Yong-young from Pohang University of Science and Technology (POSTECH) announced the development of a p-type perovskite transistor based on a cesium-tin-iodide (CsSnI₃) thin film. The device has achieved a positive hole mobility exceeding 50 cm²/V·s and a current on/off ratio surpassing 100 million (10⁸), setting a new global benchmark for p-type perovskite transistors. The findings have been published in the prestigious international academic journal Nature.
The core breakthrough of this research lies in solving the long-standing issue of air stability for tin-based perovskite semiconductors. The new device can operate stably in air for over four hours and maintain its initial performance for more than a month under accelerated aging conditions at 100°C. In contrast, previous similar devices would fail within minutes of air exposure.
The research team stated that this achievement will accelerate the practical application of p-type perovskite thin-film transistors in integrated circuits. It holds significant importance for various fields, including vertically stacked DRAM for AI computing, next-generation display driver circuits, and wearable devices.
The P-type Transistor: A "Top 10 Future Challenge" in Semiconductors
Transistors are the fundamental building blocks of chips, categorized into n-type, which transmit electrons, and p-type, which transmit positive holes (the vacancies left when electrons depart). Achieving high-performance, low-power semiconductors relies on balanced performance between these two types. However, improving the performance of p-type transistors has historically been extremely difficult and has been listed by South Korea's Ministry of Science and ICT as one of the "Top 10 Future Challenges" in the semiconductor field.
Tin-based perovskite materials have long been considered a candidate solution to this problem due to their efficient positive hole transport and performance comparable to existing oxide semiconductors. Their major flaw, however, has been extreme sensitivity to air: unreacted tin ions (Sn²⁺) remaining on the material's surface rapidly oxidize upon contact with air, generating numerous defects that impede charge flow and cause a sharp decline in semiconductor performance.
"Volatile Surface Reconstruction" Strategy Overcomes Stability Bottleneck
Professor Noh Yong-young's team proposed a solution called "volatile surface reconstruction."
By treating the surface of the CsSnI₃ semiconductor with potassium acetate (KAc), the researchers converted the unreacted tin ions that previously caused performance degradation into the volatile compound tin(II) acetate (Sn(Ac)₂), which naturally evaporates into the air. After the tin ions depart, potassium iodide (KI) spontaneously forms in situ, creating a "self-protective layer" that shields the semiconductor from external environmental damage.
This process significantly lowered the device's threshold voltage, achieving a positive hole mobility exceeding 50 cm²/V·s and a current on/off ratio above 10⁸. Regarding stability, the new device can operate continuously in air for over four hours and maintain its initial performance for more than a month under accelerated aging at 100°C, representing a qualitative leap in stability compared to previous similar devices.
Application Prospects: AI Memory, Display Drivers, and Wearable Devices
Professor Noh Yong-young stated that this marks the first time research on p-type perovskite thin-film transistors has been published in Nature, a result made possible by six years of sustained support from Samsung Display and the South Korean Ministry of Science and ICT.
He noted that this research has resolved the long-standing low stability issue of tin-based perovskite semiconductors. It will advance the establishment of long-term stability for p-type perovskite thin-film transistors and their practical application in integrated circuits. In terms of application direction, this technology is expected to serve as an important foundation for future core electronic industry technologies, including vertically stacked DRAM memory devices for AI computing, next-generation display driver circuits, wearable devices, and highly integrated semiconductor components.