Single-crystal LaB6 field emission array is rapidly fabricated by ultraviolet femtosecond laser and its field electronic structure characteristics

Abstract

The single-crystal lanthanum hexaboride (LaB6) field emission array with uniformly hill-shaped emitter morphology was quickly fabricated (30 min) using an ultraviolet femtosecond laser. The height of each hill-shaped emitter is 6 μm, and the curvature radius is 100 nm. The phase and composition analysis shows that the ultraviolet femtosecond laser has minimal thermal damage to the single crystal LaB6 array. The field emission characteristics indicate that the processed array has a starting electric field of 2.1 V/μm, and the field emission current density reaches 0.76 A/cm2. The first-principles calculation shows that the work function of single-crystal LaB6 is significantly reduced to 0.45 eV under a strong electric field (0.1 V/Å), which making free electrons easier to form electron emission. This calculation results provide a theoretical basis for our experiment. These results provide a potential path for the rapid fabrication of single-crystal LaB6 arrays with excellent field emission characteristics.