JNCASR: Super-packed organic transistors for flexible devices

“We made it in the lab using a simple templating technique,” explain K. Swathi (left) and K.S. NarayanSpecial Arrangement  

A nano-array with one billion transistors in 1 sq. cm area has been developed by researchers from Jawaharlal Nehru Centre for Advanced Scientific Research (JNCASR), Bengaluru. Though tiny, these transistors provide higher output current in comparison with conventional organic field transistors used in organic light emitting diodes.

As the new device is not rigid and uses organic semiconductor inks, it can also be used in flexible displays and sensor technology.

They developed the new vertical organic transistors called Organic Nano-Triode Array. “At 100 nm, each transistor in the circuit measures 500 times thinner than the human hair and it is half a micron in height. We made it in the lab using a simple templating technique,” explains K. Swathi from the Department of Molecular Electronics at JNCASR and first author of the paper published in Nano Letters. “In the regular organic field effect transistor, there will be 5-10 transistors in 1 sq. cm area. But in our case, about one billion transistors can be packed in the same area.”

The cost per transistor is drastically scaled down with this procedure. “Curved, flexible and foldable device technology is increasing every day and these new electronic products require smarter, slimmer circuits which can provide high throughput at low cost. Transistor technology is now shifting to 3D circuits which can pack more components in a smaller area. With this in mind, we developed the new nano-array which can house higher density of transistors,” says K.S. Narayan from the Department of Molecular Electronics, JNCASR.

The researchers carried out two types of measurements to study the capacity of the nano-array. The first one is the typical transistor measurement of the entire array. The second set of measurements involved studying each pore of the array and demonstrating its transistor action. They concluded that the new transistor can be turned-ON to the high conducting state with a low voltage of less than 3 V.

The molecular electronics laboratory at JNCASR is building a portfolio of different devices in the area of organic electronics. Further design and development is needed to fully address these vertical transistors as functional blocks to build circuits.