Enhanced luminescence of Si(111) surface by localized surface plasmons of silver islands

The role of silver localized surface plasmons (LSPs) on the luminescence of a Si(111)-(7 x 7) surface has been investigated by scanning tunneling microscopy (STM) with a silver tip at 77 K. On a bare Si(111)-(7 x 7) surface, a characteristic peak at 1.85 eV dominates the STM-induced luminescence spectrum, although the luminescence intensity is extremely weak. Once Ag atoms are deposited onto the Si surface to form islands with a few atomic layers, it is found that the intensity of the characteristic peak from the Si surface underneath the Ag islands is significantly enhanced by about one order. In addition to the luminescence from the Si surface, light emission originating from the irradiation decay of the Ag plasmons is also detected. Such great enhancement of the luminescence from the Si surface is attributed to the strong coupling between the surface states of the Si and the LSPs of the Ag islands.

Automated summary

The role of silver localized surface plasmons on the luminescence of a Si(111)-(7 x 7) surface was investigated using scanning tunneling microscopy at 77 K. It was found that the luminescence intensity from the Si surface underneath the Ag islands was significantly enhanced by about one order due to the strong coupling between the surface states of the Si and the LSPs of the Ag islands. In addition, light emission originating from the irradiation decay of the Ag plasmons was also detected during the study.