Synthesis of morphology-improved single-crystalline iron silicide nanowires with enhanced physical characteristics

Abstract

Single-crystalline iron silicide nanowires were synthesized via an original approach, pre-deposition method (PDM), with significantly improved morphologies and physical characteristics as compared with those fabricated by conventional chemical vapor deposition. In the pre-deposition method, combining rapid thermal annealing (RTA) and chemical vapor deposition (CVD), iron silicide nanowires grew from the heterogeneous nucleation sites on the surface of the thin film without a catalyst or Al₂O₃ template. The morphology of the nanowires has been considerably improved in terms of alignment and aspect ratio. HRTEM analysis confirms that the nanowires were β-FeSi₂ with a crystal direction of [111]. Physical property measurements indicate that compared with CVD β-FeSi₂ nanowires, β-FeSi₂ nanowires synthesized by the PDM performed better in both the field emission and magnetic properties. Magnetic property measurements show that the coercive field of PDM nanowires increased from 249 Oe to 900 Oe. Field emission studies reveal that the average β value of the CVD β-FeSi₂ nanowires was 1060, while that of the PDM nanowires became 1892. Notably, with a furnace, few researchers can successfully synthesize nanowires of β-FeSi₂, which is one of the most fascinating silicides for its important applications.