Nanocomposites and nanomaterials
Appearance of hybrid states in a structure ultra-thin silicon film covered with a monolayer of metal nanoparticles

V. Lozovski,1 C. Lienau2, G. Tarasov,3 T. Vasyliev 1, Z.Y. Zhuchenko3

1 Taras Shevchenko National University of Kyiv, Volodymyrska, 60, Kyiv-01033, Ukraine
2Institut für Physik Fk. V Carl von Ossietzky Universität Oldenburg Ammerländer Heerstraße114-118 D-26129 Oldenburg
3V.E. Lashkaryov Institute of Semiconductor Physics, National Acad. of Sci. of Ukraine, Prospect Nauki 45, Kyiv-03028, Ukraine
Email: tarasov@isp.kiev.ua
Covering of the semiconductor surface with particles is common in experimental studies of the optical properties of nanoparticles systems. As a rule, the main attention is paid to either plasmon resonance in the system of metal nanoparticles (NPs) deposited unto non-absorbing silicon substrate, or the practical use of nanocoatings in the structural elements of solar cells. However, experimentally it has been shown that absorption in silicon films significantly depends on plasmonic properties of metal nano-inclusions and coverings. It has been shown also that there exists a principal possibility of enhancing of absorption of external light in a metal-semiconductor nanostructure.
In this report the absorption of external light by NPs covering – ultrathin a-Si film system is studied for different type of NPs and for ultrathin silicon film of different thicknesses. The coverage of absorbing a-Si by system of metal NPs of identical orientation and shape is considered theoretically. Silicon film thickness is taken to be in range 80-200nm. NPs symmetry axis is perpendicular to the surface of silicon surface. NPs are of 10 nm radius in plane of a-Si film. There is a SiO2 layer of 10 nm thickness placed between submonolayer coverage and silicon film. Spectral properties of considered system was studied by means of effective susceptibility concept. The purpose of these studies was also to find system configuration when enhancement of absorption in ultrathin a-Si films can develop for the NPs of limited sizes. Dependence of absorption of external light by NPs covering – ultrathin a-Si film system on its morphology and type of metal NPs is established. For chromium and osmium NPs coverage with chromium and osmium NPs the appearance of hybrid nano coverage-silicon mode is predicted.