Surface structure and photoemission studies of nanocrystalline TiO2 layer/ITO coated glass interface

Room temperature growth of nanocrystalline TiO2 thin film was carried out by two-electrode cell. The film was characterized by surface probing techniques. Morphological studies revealed that film's grains are evenly distributed across substrate surface. Average height of grains distribution is below 64 nm. Post-deposition annealing aided film's particles' orientation in a structure that resulted in compact layer. Average crystallite size was estimated as 19.5 nm. Quality and chemical states of film composition were observed by core level photoemission studies. From XPS studies, small shift (∼0.11 eV) observed in binding energy position of Ti 2p3/2 corroborated oxidation states of titanium species found in TiO2 structure. Peak broadening and formation of InOSn linkage at oxygen valence band indicated interactions between substrate's atoms due to annealing. Apart from substrate's atoms interaction, chemical state of Ti profile remained stable implying no major chemical interaction between ITO atoms and film components. This study demonstrated TiO2 as a recipe for stable barrier layer capable of hindering charge trapping in nanostructured photonic devices.