A new process for the stabilization of vertically aligned GdB6 nanorods and their field emission properties

Abstract

Display devices and electron-emitting materials based on rare-earth hexaborides have attracted considerable research interest due to chemical inertness and low work function. These properties make them perfect materials for field emission. Here, a low-temperature process for the stabilization of GdB₆ nanorods using Gd(OH)₃ nanorods and NaBH₄ has been designed. The synthesis of a gadolinium hydroxide precursor was done via a hydrothermal route at 120 °C. Further, the as-obtained ultrafine nanorods of Gd(OH)₃ were mixed with sodium borohydride and annealed at 1000 °C in an inert atmosphere at a slow heating rate (40 °C h⁻¹). Transmission electron microscopy (TEM) results of GdB₆ showed the formation of ultrafine nanorods (40 nm × 150 nm). Interestingly, we have observed the formation of a rod-like morphology of GdB₆ because of the slow heating rate (40 °C h⁻¹) employed during the annealing process. Furthermore, the GdB₆ film was fabricated on Si-substrate using ultrafine GdB₆ nanorods via a spin coating method. The atomic force microscopy (AFM) study of the GdB₆ film showed the presence of vertically aligned GdB₆ nanorods. The field emission study of the vertically aligned GdB₆ nanorods showed low turn-on field (4.4 V μm⁻¹) and high enhancement factor (β = 1490).