The femtosecond laser micro-processing of the field-emission tip arrays in single crystal CeB6

The field-emission tip arrays (FEAs) in single crystal cerium-hexaboride (CeB ₆) were micro-processed by femtosecond laser. The results show that the femtosecond laser has no damage to the surface structure and phase of the CeB ₆ FEAs, and the FEA with the curvature radius of the optimal tips of about 0.6 μm and the height of about 5 μm have uniform morphology and the best field-emission performance. The single crystal CeB ₆ FEAs had good emission stability under the following conditions: the starting electric field of 2.8 V/μm and an emission current density of 0.98 A/cm ² at an electric field of 7.7 V/μm. The calculations of material removal threshold and finite element simulation of the temperature field substantiate that laser peak energy density F ₀=0.95 J/cm ² is in good agreement with the theoretical calculation result (0.51 J/cm ²≤F ₀ ≤ 2.12 J/cm ²). Finally, the best process parameter range of this experiment is obtained. These results further indicating that the femtosecond laser micro-processing is an effective method to develop the vacuum field-emission application of single crystal CeB ₆.