Substrate modification influence on properties of nanocomposite based on TiO₂ and gold nanoparticles

In this work, we study photo-induced current transfer through nanocomposite structures consisting of the TiO₂ coating activated with plasmonic gold nanoparticles on top of pillar-like structured SiO₂. It is shown that the photo-response of the nanocomposite can be adjusted via tuning of the heterostructure topology. Processes at the interface between silicon and noble metal nanoparticle play an important role in charge carrier photo-generation. The high photo-activity in visible part of spectrum has been found in the composite, containing pillar-like silicon dioxide nanostructures. The electron transport via the SiO₂ layer from the potential well at the TiO₂-SiO₂ interface to the n-Si conduction band was explained by electron tunneling mechanism. We present the empirical qualitative model which explains experimental results and helps to separate the contributions of different transport mechanisms. (paper)