Low temperature STM/STS study of silicon nanowires grown on the Ag(110) surface

In this paper we report a Scanning Tunneling Microscopy (STM) and Spectroscopy (STS) study as a function of temperature (ranging from room to liquid helium temperature) of the Si/Ag(110) surface at different silicon coverage. In particular, partially and fully covered surfaces, both characterized by the presence of highly ordered nanowires, are examined by STM imaging and by STS spectroscopy in order to study the temperature dependence of both the nanowires structure and their peculiar metallic behavior. No evident variation was observed upon cooling from room to liquid helium temperature, both in the STM images and in the STS spectroscopy, suggesting that such nanowires maintain the same structure in the investigated temperature range. Empty states differential conductance images show a dramatic evolution as the bias voltage is increased, suggesting that electrons are confined along the direction perpendicular to the nanowires