Fabrication of zinc oxide nanoparticles deposited on (3-aminopropyl) triethoxysilane-treated silicon substrates by an optimized voltage-controlled electrophoretic deposition and their application as fluorescence-based sensors

In this study, a voltage controlled, reproducible, scalable, and cost-effective approach for depositing zinc oxide (ZnO) nanoparticles (NPs), using electrophoretic deposition (EPD) onto p-type silicon (Si) substrates, has been researched and analyzed for its feasibility with respect to electronic device fabrication and fluorescence-based sensors. Our work presents a detailed investigation to evaluate the influence of ZnO morphology, ZnO concentration, and the method of surface treatment applied to the underlying Si substrates, because these pertain to an optimized EPD system. It has been noted that the ZnO NP structures formed directly atop the (3-aminopropyl) triethoxysilane (APTES)-treated Si substrates were more adhesive, thus resulting in a higher yield of NPs over that of comparable depositions on bare silicon. Our observation is that smaller particle sizes of ZnO will increase the energy emission for fluorescence transmission, eliminate several peak emissions, obtain higher fluorescence quantum yield (FQY) efficiency, and require less excitation energy. The results obtained are promising in relation to the integration of EPD in the fabrication of nano biosensors, PV solar cells, nano electronic devices, and thin film transistors (TFTs), where ZnO improves the reliability, affordability, and increased sensitivity needed for the next generation of nanoscale devices and systems.