Creation and Luminescence of a Single Silver Nanoparticle on Si(111) Investigated by Scanning Tunneling Microscopy

We have investigated the fabrication of a single silver nanoparticle (AgNP) on Si(111) at room temperature using scanning tunneling microscopy (STM), and the luminescence of individual AgNP has been studied by means of STM light emission (STM-LE) spectroscopy. Using the field evaporation method, we succeeded in creating two types of nanostructures, i.e., AgNP and the nanohole formed by the elimination of Si atoms, on the Si substrate. It was found that two different nanostructures can be created selectively by using the appropriate electric field. STM-LE spectra of AgNP and the Si substrate exhibit the broad peak appearing in the visible light region. The peak intensity increases as increasing the AgNP size, accompanying a slight shift of the peak position. Furthermore, the theoretical calculation based on the finite-difference time-domain insight into the STM-LE from a single AgNP on the Si substrate. (FDTD) method has been used to get an insight into the STM-LE from a single AgNP on the Si substrate.