Zinc Silicate Thin Film Composites Obtained by a Sputtering Based Approach: Structural, Dielectric and Photovoltaic Properties

Abstract

This study deals with the production of zinc silicate thin films employing a solid-state reaction at temperatures ranging from 300 °C to 560 °C, to develop new inorganic, n-type materials with seemingly incompatible properties as low work function, high mobility, and high visible transmittance. Depending on a careful reaction control, zinc silicates can preserve reagents (silicon and/or ZnO) as nanoaggregate guests, exhibiting tunable light absorption and emission properties that make them useful for different applications, e.g., LED phosphors, photovoltaic windows, mesoporous photocatalytic materials for solar fuel production, etc. The main aim of this work is to obtain a zinc silicate single-phase and then determine its dielectric properties through ellipsometry. Simultaneously, as an example of application, a p-n photovoltaic junction is fabricated that exhibits a remarkable collection of photo-generated charge carriers at very high bandgaps (>2 eV). The obtained results are promising in tailoring the zinc silicate guest-host composition (appropriate Si nanostructures sizing and quantity, improved charge carrier transport properties due to the simultaneous presence of bulk zinc oxide islands) in the function of the desired application, and taking into account that proposed selected low-temperature fabrication process is strategic for safeguarding the underlying junctions of tandem devices.