Template synthesis of metal tungsten nanowire bundles with high field electron emission performance

Abstract

One-dimensional (1D) metal nanowires are of great importance for nanodevices due to their distinctive optical, electronic and mechanical properties. Here, for the first time, we report a simple H₂ reduction-assisted hard-templating approach to fabricate metallic tungsten (W) nanowire bundles by using mesoporous silica SBA-15 as a template. The metal W nanowires with a length of 300–500 nm and diameter of 5–8 nm have long-range regularity over large areas because of their inter-wire pillar connections. Each nanowire has body-centred cubic (bcc)-W crystalline structure with a [110] preferential growth direction. As a field electron emitter, the W nanowires bundles show a low turn-on field of 4.1 V μm⁻¹, a high field enhancement factor up to 3563 and good field emission stability (with a fluctuation below 5% over 32 h).