Light detection enhanced by surface plasmon resonance in metal film

Light detection enhanced by surface plasmons was confirmed in Au film/n-type Si Schottky structures. Electrons excited directly with light in Au film overflowed into the n-type silicon, and this excitation was enhanced by surface plasmons induced by Au nanorods attached to the Au film. Excitation was clearly observed in a wavelength range corresponding to the energy of less than the band gap of silicon. The feasibility of Schottky-type photodiodes, in which electrons were never generated by absorption in semiconductors but directly excited in metal, was experimentally demonstrated.