September 2026 - Page 8 of 29

A KAIST-led team has reported a single material — degenerately doped tin diselenide — that injects charge efficiently into both n-type and p-type atomically thin semiconductor channels, removing the need for a separate contact metal per polarity. The paper reports a drive current more than a thousand times higher than a nickel electrode in p-type tungsten diselenide, an on/off ratio above a billion in n-type molybdenum disulfide, a subthreshold swing below 70 mV per decade, and a monolayer CMOS inverter with a voltage gain near 340. This article explains the physics, converts the figures into engineering terms, places the result against earlier contact schemes, and sets out the distance between a laboratory inverter and a manufacturable chip.