Surface photovoltage of Ag nanoparticles and Au chains on Si(111)

We present surface photovoltage (SPV) measurements of metal nanostructures on Si(111)‐(7 × 7) using scanning tunneling microscopy and spectroscopy (STM/STS). Quantitative results are obtained from spatially resolved I(V) spectra under laser illumination. The SPV data of Ag nanoparticles deposited on Si(111)‐(7 × 7) are compared to results of a Si(111) surface partially covered by the quasi one‐dimensional Si(111)‐(5 × 2)‐Au structure. On the latter we determine the SPV as a function of laser power at different locations. An accurate value for the Fermi‐level pinning position of Si(111)‐(5 × 2)‐Au atomic chains is obtained. Based on these results we establish and discuss a simple model for the band topology. It is confirmed by spatially resolved local work function measurements utilizing the image‐state derived field‐emission resonances. The need for miniaturized high‐frequency electronics requires insight in the electronic properties of nanoscale metal–semiconductor contacts. In this work the spatially resolved band topology of metal clusters deposited on Si(111)‐(7×7) is unraveled by measuring surface photo voltages in a scanning tunneling microscope. In a supporting experiment patches of Si(111)‐(5×2)–Au serve as a model system. A simple model for the band topology is confirmed by the spatially resolved local work function.