Microstructure and field emission property of Bridgman-grown Si-TaSi2 eutectic in situ composite

Using an improved Bridgman technique with high temperature gradient (210 K/cm), directionally solidified Si-TaSi2 eutectic in situ composite with uniform and aligned TaSi2 fiber is obtained. The growth mechanism and field emission property of the Si-TaSi2 eutectic are investigated. It is revealed that the co-operative growth of two phases for Si-TaSi2 eutectic is related to the ratio of ΔSsi/ΔSTaSi2 (ΔS is the entropy of fusion). The novel TaSi2 sharp tip arrays with fiber curvature radius of 21 nm and fiber height of 2.79-6.45 µm are fabricated by selective wet etching at optimized parameters. The Si-TaSi2 cathode arrays obtained present a reasonable field emission performance with low turn-on electric field of 3.8 V/μm and threshold field of 6.5 V/μm and large emission area per tip of about 1874 nm2, which can be used as promising materials for field emitters.