ZnO nanoparticle-decorated HfO2/Sn-doped In2O3 core–shell nanowires by atomic layer deposition: enhancement of field emission behavior by surface modification engineering

Abstract

Enhanced field emission properties of Sn-doped In₂O₃ (ITO) nanowires (NWs) after the formation of a heterostructure core–shell configuration, namely ZnO nanoparticle-decorated HfO₂/Sn-doped ITO NWs, by the atomic layer deposition (ALD) process were reported and investigated in detail. Island growth of a ZnO layer on the ITO NWs, with a low density, after the ALD process was observed while for the growth of the ZnO layer on the HfO₂/ITO core–shell NWs, a ZnO layer with very tiny nanoparticles (NPs) can be achieved along the axial direction throughout the whole nanowire. A turn-on field of ∼10.8 eV with a field enhancement factor (β) of 409 can be found for the ITO NWs while the turn-on field decreases from 10.8 to 6 V μm⁻¹ with an increase in the field enhancement factor (β) from 409 to 753 after the ZnO nanoparticle growth on the ITO NW. By combining the two materials utilizing surface modification engineering, a highly dense ZnO NP decorated on HfO₂/ITO core–shell NWs can be achieved, resulting in a significant reduction of the turn-on field to 3.7 V μm⁻¹ with an excellent field enhancement factor of 1677. The findings provide an effective way of improving the field emission properties for nanodevice applications.