Korean researchers develop world's best perovskite transistor, tackling key semiconductor challenge

South Korean researchers have secured a foundational technology capable of dramatically improving the performance of p-type transistors used in smartphones.

A research team led by Noh Yong-young, a professor at POSTECH (Pohang University of Science and Technology), announced Wednesday that it has developed a perovskite semiconductor with significantly enhanced performance and stability. The findings were published in Nature.

Smartphones contain vast numbers of transistors — tiny switches that turn electrical signals on and off. These fall into two categories: n-type, which carry electrons, and p-type, which carry "holes," the vacancies left when electrons depart. Both types must work in balance to produce high-performance, low-power semiconductors, but improving p-type transistor performance has proven particularly difficult — so much so that the Ministry of Science and ICT has listed it among the "10 great future challenges in the semiconductor field."

Tin-based perovskite has long been regarded as a leading candidate for solving that problem. It allows holes to flow smoothly and can match the performance of the oxide semiconductors that currently power memory chips and high-performance displays. Its critical weakness, however, is vulnerability to air. Unreacted tin ions (Sn2+) remaining on the surface oxidize upon contact with air, generating defects that block charge flow and causing semiconductor performance to collapse almost instantly.

The team's solution is a strategy it calls "volatile surface reconstruction." When potassium acetate (KAc) was applied to the surface of a cesium-tin-iodide (CsSnI₃) semiconductor, the unreacted tin ions responsible for performance degradation converted into tin acetate (Sn(Ac)₂), a volatile compound that evaporated cleanly into the air. Potassium iodide (KI) then formed naturally in the vacated sites, creating a self-protective layer that shields the semiconductor from the external environment.

The device achieved world-leading p-type perovskite transistor performance across multiple metrics: a lower threshold voltage needed to switch the device on, hole mobility exceeding 50 cm²/V·s, and a current on/off ratio of more than 100 million (10⁸). Stability also improved markedly. While earlier devices failed within minutes in open air, the new device held up for more than four hours. It also retained its initial performance for over a month under accelerated degradation conditions at 100 degrees Celsius.

"Thanks to Samsung Display and the Ministry of Science and ICT, who believed in a subject once considered impossible and consistently provided support over the past six years, we were able to report a world first in this field in Nature," Noh said.

He added that the research "resolves the chronic stability problem that had long limited tin-based perovskite semiconductors, and advances the path toward long-term stability and integrated circuit applications for p-type perovskite thin-film transistors." He said the technology is expected to find broad application across future electronics, including vertically stacked DRAM memory devices for AI computing, next-generation display driver circuits, wearable devices and high-density semiconductor components.