The effects of buffer structure in buffer-layer-assisted growth: Grain boundaries, grooves, and pattern transfer

Rare gas thin solid films have been used to create a wide range of nanostructures through buffer-layer-assisted growth. This paper examines effects related to the microstructure of the buffer layer and demonstrates that those effects can be used to produce nanostructures with different spatial distributions. We show that ∼100 ML thick Xe films form large columnar grains through secondary grain growth when condensed on amorphous substrates at 15-40 K. The grains grow to reach diameters exceeding 30 times their film thickness. Moreover, surface grooving occurs where the grain boundaries intersect the buffer surface. The deposition of Au atoms onto these surfaces produces clusters, and warm-up induces cluster diffusion and aggregation during buffer desorption before delivery to the surface. Transmission electron microscopy results show that the grooves capture the mobile clusters and concentrate them in a fashion analogous to the capture of agitated grains of sand on a patterned surface. The grain boundaries and their grooves then offer a way to vary the cluster distribution on the surface and to print by pattern transfer using nanoscale particles of a material of choice.