Surfaces and Interfaces is an area of interest at the ESRF not only in the group formed by ID01, ID03 and ID32 but also in many other beamlines. Diffraction techniques are mostly used to investigate structural aspects of relevant interfaces. As nano-objects are currently of great interest we present here three contributions on semiconductor quantum dots. The first one shows how the anomalous scattering effect helps to differentiate strain and intermixing. The second contribution deals with Ge dots grown through a Si3N4 layer revealing how the strain is relaxed when the dot dimensions increase. The third one concentrates on SiC crystallites in a Si matrix.

Two examples of solid liquid interfaces are then presented. One of them shows that at the interface of KDP crystals in contact with water, there are two molecular layers that resemble ice more than liquid water due to the strong interactions at the interface. In the second, the evolution of adsorbed S atoms on Au(111) in an electrochemical cell containing alkanothiols was investigated as a function of the cell potential.

Finally an example of gas/solid interfaces is also described. CO chemisorbed on Ni(111) was investigated over 9 decades in pressure. At atmospheric pressure the CO layer is compressed, stiff and incommensurate with the substrate lattice.