Liquid metal prints fast transistors express
An ordinary transistor in a phone is made in a vacuum chamber, where atoms are deposited layer by layer. Expensive and slow. But indium oxide can be printed like ink — from a drop of liquid metal that, in air, coats itself with a thin oxide film.
The authors took indium, melted it, and rolled it over a substrate at 250 degrees. The result was a polycrystalline layer only 5 nanometers thick — a thousand times thinner than a human hair. Its grains are large and span the entire thickness, so electrons move almost without obstacles.
The transistor built on this film works stably: after 10,000 on-off cycles, its characteristics did not degrade. And if you add a hafnium oxide insulator, the mobility stays high—107 cm²/V·s — while leakage current is minuscule. From such transistors, the team built an inverter, a basic logic element, and it amplifies the signal by a factor of 69.8.
Printing oxide semiconductors from liquid metal is like cooking on a skillet instead of molecular gastronomy: simpler, faster, and almost as tasty. The next step is to shrink the transistors and test them in real circuits.
An indium oxide film just 5 nanometers thick is transparent to the eye but conducts electricity — which is why such materials are used in touchscreens.
In the series 'Westworld,' robots are covered with thin films that are printed on the spot — similar to this technology, but for electronics.