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The growth of endohedral fullerene La@C82 films on Si(1 1 1) has been explored by scanning tunneling microscopy (STM). The STM images reveal the molecules are hexagonally close-packed in multilayer films with the inter-molecular separation similar to that of the La@C82 crystal. Electronic properties of the films have been investigated by ultraviolet photoelectron spectroscopy (UPS) and tunneling spectroscopy, which provide comparable results for the electronic structure of the occupied electronic states. Tunneling spectroscopy also gives an insight into the unoccupied states and shows that the edges of the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) both approach the Fermi level, indicating that the film is metallic or semi-metallic. An electronic structure of the La@C82 film is proposed from the spectroscopic results.

A UHV atomic force microscope with a conducting tip is used to measure the tip–sample conductance as a function of the applied force on well-ordered, monolayer islands of C60 on Cu(111). By imaging the sample before and after each force–distance experiment, it was possible to investigate the forces required for the removal of individual C60 molecules from the islands. The removal of C60 occurs near defects or edges of the C60 islands and requires an applied force of 5–20 nN, which corresponds to applied pressures of order 1 GPa. In addition, it was possible to investigate the strength of the C60 film on the molecular scale. It was found that the mechanical stiffness of a C60 molecule is of order 6 N/m and the islands appear to undergo a reversible yield process at an applied pressure of around 1.2 GPa.

In-situ high temperature scanning tunnelling microscopy (STM) measurements were performed on vacuum-annealed, boron-doped Si(111) wafers. The samples were p-type with an atomic boron concentration of ∼ 10 19 cm −3 which were chosen such that after ultra-high vacuum processing at up to 1250°C and annealing at 600°C they gave rise to co-existence of both 7 × 7 and √3 × √3R30° surface terminations. After the initial “flashing” of the sample to 1250°C, we observe pinning of a variety of reconstructions due to the random out-segregation of boron to the surface. Prolonged annealing at the measurement temperature of 600°C was observed to give rise to the agglomeration of the boron into well-defined √3 × √3 regions. In the measurements, we observe preferential directions for the in-plane boundaries between √3 × √3 and 7 × 7 regions, showing clearly the importance of dimerisation as a strain relief mechanism between these regions. Detailed observations reveal the lateral diffusion of boron and silicon in the √3 × √3 regions as a function of time. The data are discussed in terms of the various controlling processes at the surface.

The Na-stabilised Si(111)3 × 1 phase has been investigated upon annealing. At temperatures between 410 and 540°C the Na desorbs gradually, resulting in a structural transformation to the 7 × 7 reconstruction. The use of a high-temperature STM enabled the in situ observation of this morphological transition, revealing a variety of intermediate Si(111) reconstructions such as 2 × 2, c4 × 2, √3 × √3R30°, 5 × 5, 7 × 7 and 9 × 9 on Na-free areas, before the entire surface reconstructed to the 7 × 7 structure at higher temperatures (800°C). The transition is accompanied by a pronounced mass transport and can be explained in terms of the removal of excess Si atoms from local Na-free 3 × 1 formations.

Gold clusters were deposited on graphite substrates by evaporation in an argon atmosphere. The low-temperature electronic behaviour of these samples was examined by scanning tunnelling microscopy. Isolated islands showed clear examples of the Coulomb blockade. It was possible to alter the size of the blockade and the residual charging of the clusters by adjusting the tip-sample spacing. These results may be explained in terms of the semiclassical theory of charging effects in the double tunnel junction.

The effect of the classical image potential on the tunnel-barrier heights deduced from scanning tunneling microscopy is considered. An earlier prediction that the image potential should lead to an observable difference in barrier heights as deduced from two different measurements is shown to be incorrect. Using an approximation to the full multiple image potential we find that the barrier height deduced from the variation of current with tunnel-barrier width is extremely close to the unreduced work function, and we discuss what characteristic of the image potential leads to this result.