Electron emission enhancement of long hybrid emitters prepared using ZnO nanowires decorated with Zn nanoflakes

Hybrid emitters consisting of ZnO nanowires decorated with Zn nanoflakes were prepared for electron emission applications. The ZnO nuclei, having a pyramidal shape, were deposited on the ZnO:Al buffer layer, which offered surface protrusions for vertical nanowire growth. The Zn hexagonal nanoflakes, having thicknesses of 15-20 nm, were decorated to increase the conductivity and number of emission sites of the ZnO nanowires. The field enhancement factor increased from 8623 to 18108 and the work function was reduced from 5.3 to 3.35 eV after decorating the nanowires with Zn nanoflakes. A low turn-on field of 0.65 MV/m and high current density of 1.46 mA/cm2 were obtained. The current density variation measured at 350 V was less than 23% over a measurement time of 180 min.