Relaxation of plasmons in nm-sized metal particles located on or embedded in an amorphous semiconductor

Relaxation of plasmons, generated optically in nm-sized metal particles, occurs usually via excitation of electron-hole pairs inside the particles. If a metal particle is located on the surface of or embedded in a semiconductor, plasmons may also relax via local field enhanced excitation of electron-hole pairs in the semiconductor. We derive equations describing the latter relaxation channel in the case when the semiconductor is amorphous or nanocrystalline and show that the ratio of the rates of the two channels may vary in a wide range. In particular, the latter channel may dominate under certain conditions. As an example, we briefly discuss the Ag/TiO2 system.