This facility based at the ENEA laboratories is hosted in a 35 l ionically pumped ultra-high vacuum vessel endowed with a home made STM, a Z inertial piezo slider for sample approach and a remotely controlled ρ,θ,φ nanomanipulator for sample movement with submicron precision. The vessel has two load-lock chambers for tip and sample load and a hand actuated wobbling pincer for manual operations. It also has optical ports for access to the tip region by two different laser beams.
Above on the left is the scheme of the UHV STM system coupled to the available laser sources and to the spectroscopic analysis system devoted to “tip-enhanced” photoluminescence studies. On the right, a photograph of the UHV vacuum vessel with its lid lifted shows details of the optical microscope case and of the STM. Below, an optical microscope image of the STM tip over a layer of Rhodamine 6G fluorescent dye in white light (left) and excited by a green laser (540 nm) as recorded through a long wavelength pass filter with cutoff at 560 nm with the tip within tunnelling distance (center) and 5 μm away from the surface (right). Light from the tip-enhancement area is spatially selected by a moveable pinhole and analyzed by a monochromator producing the R6G emission spectrum reported below.