Formation of nanostructures during coagulation of semiconductors in superfluid helium

Abstract

As in the case of metals, laser ablation of germanium and silicon in superfluid helium leads to the formation of thin nanowires; spherical nanoclusters are also present in ablation products. A decrease in the resistance of bundles of silicon nanowires with increasing temperature is typical of semiconductors. Laser ablation of amorphous graphite also leads to the formation of quasi-one-dimensional structures, but there are no spherical clusters among the coagulation products. The structure of carbon filaments is amorphous; they contain onion-like entities, and nanodiamonds appear as coagulation products when the concentration of carbon introduced into superfluid helium increases. The peculiar behavior of carbon is associated with the impossibility of its melting at low pressures.