Quantum effects are seen in microscopic structures in which nanometer-scale conductive wires (nanoscale quantum conductors) are arranged. Structures in which those wires are artificially arranged by taking advantage of this property are called “Nanoscale Quantum Conductor Arrays.” They have the potential to become the core of computers, far superior to the current level.
This research project was aimed at giving a memory function or computing power to nanoscale quantum conductors by arranging the conductors in an appropriate mutual relationship. In order to measure and control nanoscale quantum conductors in several nanometers which are extremely minute distances, multiple probes for scanning tunneling microscopes were newly developed. With the use of the probes, reversible control of polymerization and depolymerization of fullerene C60 was successfully performed, thereby achieving the foothold for memories of high density which is several hundred-fold higher than the current memory densities. And the measurement of the quantum conduction property of carbon nanotubes was successfully performed, thereby confirming that this is also effective as a scanning tunneling microscope under which multiple probes can be manipulated in the nanoscale range. An atomic switch integration technique using silicone materials was developed and operation at about 1 GHz was confirmed, thereby putting a landmark for its application to high-speed logic devices. In addition, a nanowire fabrication technique using various materials such as metals and organic molecules was developed, the metal-to-insulator transition was observed with injection of electronic charge into organic molecular (polydiacetylene) nanowires, and the potential for new device materials was seized.
This research project was carried out jointly by us with Cambridge University in the UK, in a complementary manner by bringing the respective strengths: the nanometrological technique for multiple-probe microscopes from Japan and nanoprocessing techniques such as electron beam method from the UK. The outcomes are expected to lead to a new nanoelectronics world in the future, in ways such as realizing novel computer architectures.