For speedier electronics, Indian scientists create transistor utilising single molecules

In a breakthrough in electronics, scientists at the S. N. Bose National Centre for Basic Sciences, an autonomous institute, developed a unique transistor using single molecules.

The novel transistor is controlled by mechanical forces rather than traditional electrical signals.

This “could pave the way for advancements in areas like quantum information processing, ultra-compact electronics and sensing applications”, the team said.

The researchers used a piezoelectric stack to meticulously break a macroscopic metal wire to create a sub-nanometer gap precisely sized for a single molecule like ferrocene in a technique known as mechanically controllable break junction (MCBJ).

“This molecule, structured with an iron atom sandwiched between two cyclopentadienyl (Cp) rings exhibits altered electrical behaviour when mechanically manipulated, demonstrating the potential of mechanical gating in controlling electron transport at the molecular level,” the team said.

The team led by Dr Atindra Nath Pal and Biswajit Pabi discovered that the orientation of ferrocene molecules between silver electrodes significantly affects the transistor’s performance. Depending on the molecular orientation, the device can either enhance or diminish electrical conductivity through the junction, underscoring the importance of molecular geometry in transistor design.

With further research, the team explored gold electrodes with ferrocene at room temperature. The combination resulted in a surprisingly low resistance, nearly five times the quantum of resistance (around 12.9 kiloohms), but significantly lower than the typical resistance of a molecular junction (around 1 megohm). Ohms are used to measure the electrical resistance of a material or device.

“This suggests the possibility of creating low-power molecular devices. These devices could pave the way for advancements in areas like low-power molecular devices, quantum information processing and sensing applications,” the team said. The findings are published in the journal Nano Letters and Nanoscale.