Nanostructured rhodium films produced by pulsed laser deposition for nuclear fusion applications

In this paper the possibilities offered by pulsed laser deposition (PLD) for the production of nanostructured rhodium films with improved properties are explored. Thanks to its high reflectivity and low sputtering yield, rhodium is one of the best candidates for the development of thin films to be used in first mirrors, which are crucial components in many diagnostic systems of thermonuclear magnetic fusion machines, like tokamaks. Due to the features of PLD, by varying the process parameters it is possible to tailor both the structure, i.e. the nanocrystalline domain size of the deposited films, down to less than 5 nm and separately control the other relevant physical properties. This leads to modifications in growth regime and annealing dynamics, in such a way that both morphology and reflectivity achieve the properties demanded to use these films as mirrors for fusion applications, opening at the same time new possibilities for the future improvement of thermo-mechanical and adhesion properties.