The future development of the electronics industry depends on whether new ways to replace and surpass existing silicon-based semiconductor technologies can be found. Molecular electronics is considered to be one of the more feasible frontier technologies. Recently, the research work of the Royal Institute of Technology in Sweden has made possible the large-scale production of nanoscale electrodes, which is expected to promote the rapid development of molecular electronics. The research work was completed by a research team of the Royal Institute of Technology's micro-nano system. They developed a new technology that can produce tens of millions of nanoscale molecular junctions. These molecular junctions are composed of a pair of micro-electrodes with a nanometer spacing. They can capture and test molecules and are an indispensable tool for molecular electronics research.
The new technology uses a thin film of gold to cover the fragile material to form a molecular junction, which can be applied to the 100 mm diameter silicon wafer production process. It can produce 20 million nano-molecules with an electrode spacing of less than 10 nanometers within 5 hours. Knot. In addition, the research team of the Royal Institute of Technology of Sweden also conducted electrical tests on the fabricated molecular junctions in cooperation with the Van der Sant Laboratory of Delft University of Technology in the Netherlands. They trapped reference molecules widely used in the field of molecular electronics with a width of less than 10 Studies in the nanometer molecular junction electrode gaps have found that new production technologies do not hinder the formation of molecular junctions. Researchers point out that the new technology breaks through the bottleneck of large-scale production of nano-scale electrode-pitch molecular junction devices, making it possible to make single-molecule electronic devices in the future.
The key link of the new technology is to form a nano-scale electrode gap that can generate a quantum tunneling effect, so that the electrons in the circuit can cross the barrier to achieve tunneling. The size of such a broken junction is usually only a few atomic magnitudes, which can cut off the flow of current. However, because the gap is too narrow, electrons with sufficient energy can tunnel through this region. These tunneling electrons can form a weak but measurable tunneling current, which is very sensitive to the nanomolecules in the gap-size gap.
Fractured molecular junctions are the best technical approach to single-molecule circuit testing, and it is expected to achieve ultra-sensitive and high-speed molecular detection. However, tunnel fracture molecular junctions can only produce one gap at a time, hindering the application of this technology. To solve this problem, the research team of the Royal Institute of Technology of Sweden first used photolithography to cover a layer of gold film on the surface of titanium nitride to form a stack structure, and then placed it on the surface of a silicon wafer. The stack structure formed a gap under the action of concentrated stress When the silicon under the stack is removed (this process is called the release corrosion process), micro-cracks will be formed in the pre-designed position in the titanium nitride to release the stress, thereby further deforming the gold thin film and gradually forming a span. Atomic-sized filaments of cracks, after the filaments break, an electrode gap with a width of less than 10 nanometers is formed.
Researchers point out that the new technology can also be applied to other conductive materials besides gold, and potential application areas include molecular electronics, spintronics, nanoplasma, and biosensing.