KAIST researchers solve electrical bottleneck blocking next-generation semiconductors

South Korean researchers have developed a new structure that could resolve the "electrical bottleneck" — long considered the biggest technical obstacle in next-generation semiconductor development.

KAIST announced Monday that a research team led by professors Hong Seung-bum and Kang Ki-bum of the Department of Materials Science and Engineering, working with a team led by professor Cho Seong-bum of Sungkyunkwan University, has developed a new structure in which electricity flows without obstruction through a two-dimensional material — an ultrathin film just one or two atomic layers thick — and built an analytical platform capable of directly observing this phenomenon at the nanometer scale.

In semiconductors, contact resistance at the junction where a metal electrode meets the semiconductor material degrades performance and causes power loss. As semiconductors shrink, the impact of contact resistance grows, making it one of the most formidable technical challenges in next-generation chip development.

Rather than attaching a metal electrode on top of the semiconductor as is conventionally done, the team created semimetallic and semiconducting regions continuously within a single two-dimensional material, allowing the two regions to connect naturally within the same material. Using platinum diselenide — a two-dimensional material just one atomic layer thick — they demonstrated for the first time that current can flow across the boundary without obstruction, presenting a new structure in which the two regions form a seamless monolithic unit.

The team used atomic force microscopy to directly visualize, at the nanometer scale, how charge carriers move within the thin film.

They confirmed that as current moved from the semimetallic region into the semiconducting region, it flowed naturally without any electrical bottleneck — no blockage or redirection. This marks the first experimental proof that a monolithic interface does not impede current flow.

The team also applied an electric field to the semiconducting region in the same way a real transistor controls current flow, verifying the device's operation. The results confirmed that current flow could be stably controlled within the combined metal-semiconductor structure, demonstrating its potential as a next-generation electronic device.

The findings could find broad application in next-generation two-dimensional electronic devices, ultra-high-speed computer processors, low-power semiconductor chips, and miniaturized hardware for emerging fields such as AI.

"This research confirmed that charge carriers flow continuously across the topological boundary between the semimetal and semiconductor regions without a distinct resistance barrier, and that the resulting semiconducting region can be successfully modulated by an electric field to function as a transistor," professor Hong said.

The findings were published in the July issue of Matter, an international journal in the field of materials science.