Determination of electronic properties of nanostructures using reflection electron energy loss spectroscopy: Nano-metalized polymer as case study

Abstract

In this work, Au was deposited with nominal effective thickness of 0.8nm on polystyrene (PS) at room temperature. According to previous study, using XPS peak shape analysis [S. Hajati, V. Zaporojtchenko, F. Faupel, S. Tougaard, Surf. Sci. 601 (2007) 3261–3267], Au nanoparticles (Au-NPs) of sizes 5.5nm were formed corresponding to such effective thickness (0.8nm). Then the sample was annealed to 200°C, which is far above the glass transition of PS. At this temperature, the Au-NPs were diffused within the depth 0.5nm–6.5nm as found using nondestructive XPS peak shape analysis. Electrons with primary energy 500eV were used because the electronic properties will then be probed in utmost surface (∼1 IMFP range of depths that is 1.8nm for PS). By using QUEELS software, theoretical and experimental electron inelastic cross section, energy loss function, electron inelastic mean free path and surface excitation parameters were obtained for the sample. The information obtained here, does not rely on any previously known information on the sample. This means that the method, applied here, is suitable for the determination of the electronic properties of new and unknown composite nanostructures.