Nano scale Titania thin film morphology and optical study on patterns of self-assembled monolayers

摘要

We report Titania thin film deposited on micron scale composite self-assembled monolayers (SAMs) pattern of polar (-COOH, -N) and non-polar (-CH3) molecules. Metallic thin films of Titania were deposited on top of SAMs patterns using physical vapor deposition system. Extensive AFM study shows that deposited films were uniform on polar SAMs and non-uniform, cluster like, on non-polar SAMs. Furthermore, AFM images clearly show clusters are like uniformly distributed nanostructures in non-polar SAMs regions up to 8 nm of Titania deposition which becomes uniform film with increased thickness. Photoluminescence spectra of TiO2 on polar and non-polar SAMs clearly shows thickness dependent UV shift and extra PL peak when compared with PL spectra of TiO2 deposited on Au thin film. Such variation in PL response was not observed when similar thickness TiO2 films were formed on Au surface without SAMs in identical conditions.