Impact of nanoporous metal oxide morphology on electron transfer processes in Ti-TiO2-Si heterostructures

By sol-gel synthesis a nanosized porous layers of TiO2 with different porosities and specific surface area were fabricated on silicon substrates. The created Ti-TiO2-(n,p)Si heterostructures were studied by the impedance spectroscopy. The significant influence of structure of porous TiO2 and type of silicon substrate on the dependence of capacity and active conductivity on an applied voltage bias is observed. In the frame of the proposed equivalent circuit model the analysis of the contribution of nanocrystals and intercrystalline boundaries into electron transfer processes is carried out. It is observered the effect of negative differential conductivity that is governed by the changing of the capture of injected electrons and holes in porous-TiO2.