A joint research group of Hiroshima University, the University of Tokyo, and the University of Hyogo has shown that black phosphorus may be useful as a material for ultra-high-speed communication devices.
In recent years, two-dimensional monoatomic layer crystals have received a great deal of attention as materials for electronic and optical devices.Among them, graphene, which consists of only one layer of carbon atom, is not only easy to bend and hard to break, but also has Dirac electrons with an apparent mass of zero, so research is being conducted all over the world.Dirac electrons have been attracting attention as a promising candidate for next-generation devices because they have the property of "continuing to move" regardless of impurities and defects, but it is difficult to increase the signal on / off ratio. , Leaving a big problem in practical use.
To solve this problem, the group focused on "black phosphorus," which has a large on-off ratio and a bandgap in the infrared region.In order to know whether black phosphorus is a suitable material, the conduction electrons generated by light absorption were directly observed, and the "presence or absence of knocking up" and "duration of the knocking up state" of the electrons were investigated.With ordinary metal, the irradiated light is reflected, and it is difficult for electrons to be launched.Even if it happens, it is said to have a duration of several picoseconds, but in this study, when black phosphorus is irradiated with a near-infrared light pulse, electrons are knocked up, which has a long duration approaching nanoseconds. It was revealed for the first time in the world to show.
This result suggests that Kurorin is one of the key materials for next-generation ultra-high-speed optical communication devices.
Paper information:[Scientific Reports] Prolonged photo-carriers generated in a massive-and-anisotropic Dirac material
