Silicon nanocrystals (Si-NCs) embedded in SiOx ensemble: First Results

For the past several years silicon nanocrystals (Si-NCs) embedded in dielectric layers have been extensively investigated for potential applications in the fields, such as optoelectronics and photonics. The literature reports that materials which are composed of alternating layers of Si-NCs and dielectric films exhibit an increased optical band-gap with decreasing NCs size.

The NaMSeN project (Nanophotonics with metal – group-IV-semiconductornanocomposites: From single nanoobjects to functional ensembles) aims at the developing of the technology of Metal-Oxide-Semiconductor (MOS) structures with Si-NCs films embedded in silicon oxide (SiOx) ensembles. In contrary to standard methods of Si-NCs formation by means of Plasma-Enhanced Chemical Vapor Deposition (PECVD) of amorphous silicon (a-Si) with following high-temperature recrystallization/annealing processes, in the course of this work colloidal Si-NCs are fabricated by chemical synthetic method. The all-inorganic Si-NCs have very heavily B and P doped shells, which induce negative potential on the surface and prevent the agglomeration by electrostatic repulsions.

The NaMSeN project aims to advance the field of group-IV semiconductor nanostructures in the new stage closer to photonic applications by overcoming intrinsic limitations of these materials (namely the low absorption cross section and emission rate due to the dominating indirect transitions) via formation of metal-semiconductor nanostructural composites and alloys (SiGe, heavy doping Si:B,P etc.) The enhancement of optical properties should be achieved mainly by exciton – plasmon coupling, Purcell effect and crystal lattice modification by strain. The project includes development of relevant technologies, theoretical models and characterization methods. The nanocomposites will be studied on different scales from single nanoobjects, microscopic ensembles, up to test devices.

More results you can find on the poster (below) presented at EMRS Fall Meeting 2016.