Photosensitive Heterostructures on the Basis of Nanocrystal Porous Silicon

Abstract

In this work the investigations of technology, morphology, electric and photoelectric properties of the silicon photosensitive structures have been represented. The structures included layers of the silicon carbide and the porous silicon. The porous layer was formed on the surface of the single crystal silicon substrates by the method of electrolytic etching in fluoride containing solutions. Plates with different microrelief surface (polished, honed, textured) were used. Carbidization of the samples leading to the formation of heterostructures on SiC/Si was conducted by the method of gas endotaxin in a hydrogen stream in a vertical reactor with cold walls and a graphite container. The structure and composition of the SiC/Si heterostructures on the different surface structures of poly − and single crystal silicon, including surface of porous silicon layer have been investigated. We show that in the process of endotaxy of all types of surfaces forms a single crystal silicon carbide phase of cubic modification. The morphology of the resultant structures has been investigated by scanning and transmission electron microscopes. Different filiform formations were found on the pore − free surface, which are identified as silicon carbide, and the cylindrical or conical structures of the unclear nature were observed on the porous surface. The current − voltage and current − power curves have been plotted for all types of the structures, the general appearance of which indicates the presence of several potential barriers. The photoelectric properties of the structures have been analyzed along with the prospect of their use in solar cells.