Photoresponse enhancement in the near infrared wavelength range of ultrathin amorphous silicon photosensitive devices by integration of silver nanoparticles

We have investigated the contribution of localized surface plasmon polaritons (LSPPs) in silver nanoparticles with radii smaller than 20 nm to the photocurrent of ultrathin photosensitive devices based on amorphous silicon. An increased light absorption and an enhanced photocurrent are found for wavelengths between 600 nm and 1150 nm in presence of nanoparticles. As amorphous silicon absorbs light efficiently only at wavelengths up to 750 nm, the increased photocurrent in the near infrared range is explained in terms of LSPP-induced photoemission of electrons within and in close vicinity of the nanoparticles.