Flexible three-dimensional CeB₆ nanowire arrays and excellent field emission emitters

We have developed an effective chemical-vapor-deposition method to fabricate large-scale cerium hexaboride nanowire arrays on flexible carbon substates. The nanowires show diameters of 80–200 nm and lengths of 5–30 μm. The high resolution transmission electron microcopy (HRTEM) indicates that the nanowire is of high crystalline with the growth orientation of [001]. The field emission of these nanowires shows favorable electron emission properties, including the turn-on fields of 1.76 V μm⁻¹, threshold fields of 3.60 V μm⁻¹ and high field emission enhancement factors of 2203 ± 27, respectively. The field emission properties depending on the gap between the anode and cathode are also investigated. The results show that the turn-on fields and threshold fields decrease from 1.76 and 3.60 V μm⁻¹ to 1.28 and 2.77 V μm⁻¹, respectively; whereas the field emission enhancement factors increase from 2203 ± 27 to 4012 ± 66 with the anode-cathode distance increasing from 500 to 700 μm. The excellent field emission performances indicate the promising application prospects of this material in flexible electronics and optoelectronics, such as high light electron sources, flat panel displays and thermal electrical power converters. - Highlights: • In this study we fabricate flexible CeB₆ nanowire arrays via CVD method. • The arrays are high-quality single-crystalline in large-scale. • The arrays show excellent field emission performances. • With anode-cathode distances increasing, E_to and E_thr fall down and β increase.