Magnetic Field Assisted Spark Discharge-Generated Gold Nanostructures: XPS Study of Nitrogen Gas Fate and Chemical Composition of Gold Thin Films

The sparking discharge process utilises high voltage to melt and evaporate tips of electrodes to create particles that can be deposited on substrate. In our research, we examine the influence of a magnetic field and nitrogen flow on gold thin-film formation onto quartz substrate. A positive effect of nitrogen flow and a 0.3 T external magnetic field was observed, in enhancement of surface plasmon band in UV visible and dispersal of nanoparticles without agglomeration. We also detected and described nitrification occurrences of gold measured by XPS at 407 eV and nitridification of quartz substrate on which gold particles are collected. These nitrogen-based chemical reactions occurred during sparking of gold wire inside of ambient air and in the magnetic field, as well during pure nitrogen flow. We measured the valence band electronic structure of gold nanoparticles deposited onto quartz substrate and found that gold thin film prepared in the magnetic field under nitrogen flow has the lowest value of 1.5 eV. Preparation of gold thin films in the magnetic field under nitrogen flow offers a highly dispersed and convenient method for productions of thin films.