Optical and structural properties of composite Si:Au layers formed by laser electrodispersion

Composite Si–Au layers prepared by laser electrodispersion with different Si:Au ratios are studied. The microscopic structure of the layers is established and their Raman spectra and optical transmission and reflectance spectra are investigated. It is demonstrated that the sputtering of a two-component Si–Au target radically changes the layer morphology. With increasing Au content in the target, the layers become inhomogeneous and a large number of inclusions arise, which contain silicon nanocrystals and a certain amount of gold. Upon the sputtering of a two-component target, inclusions are most likely formed from large molten droplets, which are ejected from the target and do not manage to divide into nanoparticles. The nanocrystalline structure of the inclusions is attributed to the slow inhomogeneous cooling of particles on the substrate. It is concluded that variations in the photosensitivity spectra of heterostructures with the investigated layers are caused by the formation of inclusions containing silicon nanocrystals with the addition of gold.