A unique transistor developed using single molecules controlled by mechanical forces could pave the way for advances in areas such as quantum information processing, ultra-compact electronics and sensing applications.
In a major breakthrough in electronics, scientists at the S. N. Bose National Centre for Basic Sciences, an autonomous institute, have developed a unique transistor using single molecules controlled by mechanical forces instead of conventional electrical signals.
Using a piezoelectric stack, the researchers carefully break a macroscopic metal wire to create a precisely sized sub-nanometer gap for a single molecule such as ferrocene. This technique is known as a mechanically controlled break junction (MCBJ). This molecule, composed of an iron atom between two cyclopentadienyl (Cp) rings (see diagram of the molecule, Figure 1), exhibits altered electrical behavior when mechanically manipulated, demonstrating the potential of mechanical gating in controlling electron transport at the molecular level.
Through experiments and calculations, Dr. Atindra Nath Pal and Biswajit Pabi, along with their team, found that the orientation of ferrocene molecules between silver electrodes significantly affects the transistor performance. Depending on the molecular orientation, it can increase or decrease the electrical conductivity through the device junction, which underlines the importance of molecular geometry in transistor design.
Further research investigated the electrodeposition of gold with ferrocene at room temperature. This combination resulted in a surprisingly low resistance, about five times the resistance of gold (about 12.9 kΩ), but much lower than the typical resistance of molecular junctions (about 1 MΩ). This raises the possibility of creating low-power molecular devices. These devices could pave the way for advances in areas such as low-power molecular devices, quantum information processing and sensing applications.