Microstructure characteristics and interface morphology evolvement of Si-TaSi2 eutectic in situ composite for field emission

As one of the semiconductor-metal eutectic (SME) composites, Si-TaSi2 eutectic composite has many characters such as the high melting point of TaSi2 material, the large density of TaSi2, fibers incorporated into the Si matrix, three-dimensional array of Schottky junctions grown in the composite spontaneously. So it is an ideal candidate for field emission array cathodes. In this paper, the directionally solidified Si-TaSi2 eutectic in situ composite for field emission is prepared by means of the electron beam floating zone melting (EBFZM) technique on the basis of Czochralski (CZ) method. The Si-TaSi2 cutectic in situ composite, which has high-aligned and uniformly distributed TaSi2 fibers in the Si matrix, can be obtained when the solidification rate changes from 0.3 to 9.0 mm/min. As the solidification rate is increased, both the fibers' diameter and inter-rod spacing are decreased, while the fibers' density and the volume fraction are increased. Moreover, the transition from a planar interface to cellular interface and then to planar interface morphologies with increasing velocity is observed with the zero power method. (c) 2007 Elsevier B.V. All rights reserved.