Ultraviolet Wavelength Identification Using Energy Distribution of Hot Electrons

Light wavelength identification is essential for many optical and optoelectronic applications. Here, we report a novel wavelength identification photodetector based on the energy distribution of hot electrons at the metal/insulator interface. The information of the light wavelength can be stored in the energy distribution of the hot electrons, which can then be readout in the form of the current-voltage characteristics. On the basis of this principle, the high-reliability wavelength identification of the monochromatic light has been realized with a simple Al/SiO₂/Si structure. The device has an excellent stability with dark current below 1 × 10^-7 A/m². Moreover, the wavelength of the monochromatic light in the deep ultraviolet range can be identified. This new principle will pave a new solution to design high-performance single-chip wavelength identification photodetectors and integrated miniaturized wavelength identification systems.