Influence of Contact Material on Photoinduced Current Flow in Si/TiO2/GNPs/TiO2 Nanocomposites

The aim of this work was to obtain Si/TiO2/GNPs/TiO2 nanocomposite coatings photoactive in the visible wavelength range. A method to increase the optical response of the oxide nanostructures is proposed. It combines a magnetron deposition of oxide matrix with the thermal deposition and aggregation of metallic nanoparticles, allowing the preparation of wide band gap oxide heterostructures with buried plasmonic Au nanoparticles. Thin 2D layers of TiO2 was deposited by reactive magnetron sputtering, followed by 2.5 nm gold layer thermal deposition and N2-atmosphere thermal annealing at 550 °C to induce coalescence of Au nanoparticles. Then Si/TiO2/GNPs was covered with TiO2 by reactive magnetron sputtering. For the electrical properties of the formed nanocomposites study, special samples were prepared on silicon substrates. Various metals were used as electrical contacts: Ti, V, Cr, Al, Zr, Au alloy Ti70-V30. The I–V characteristics of different ohmic and Shottky contacts were obtained in the presence and absence of VIS irradiation.