Scanning tunneling microscopy investigation of growth of self-assembled indium and aluminum nanostructures on inert substrates

The growth and surface morphology of indium and aluminum nanostructures on highly oriented pyrolytic graphite (HOPG) and molybdenum disulphide (MoS₂) surfaces were investigated using scanning tunneling microscopy in ultra-high vacuum. Mostly triangular and hexagonal In islands with (111) orientation were obtained along the steps of HOPG at room temperature (RT). Triangular, round-shape and large irregular In islands were found on MoS₂ surfaces at different growth conditions. Al island chains as well as isolated triangular islands were found on HOPG whereas nanoparticles and ramified Al islands were obtained on MoS₂ at RT. The shapes of these self-assembled metal nanostructures were controlled by varying growth conditions. The different shapes of nanostructures on these inert substrates can be explained in terms of differences in energetic and kinetic properties of atoms and clusters of each elements as well as the nature of substrates.