Fabrication of Large-Scale Single-Crystalline PrB₆ Nanorods and Their Temperature-Dependent Electron Field Emission

Abstract

A simple catalysis-free approach that utilises a gas–solid reaction for the synthesis of large-scale single-crystalline PrB₆ nanorods using Pr and BCl₃ as starting materials is demonstrated. The nanorods exhibit a low turn-on electric field (2.80 V µ-b;m⁻¹ at 10 µ-b;A cm⁻²), a low threshold electric field (6.99 V µ-b;m⁻¹ at 1 mA cm⁻²), and a high current density (1.2 mA cm⁻² at 7.35 V µ-b;m⁻¹) at room temperature (RT). The turn-on and threshold electric field are found to decrease clearly from 2.80 to 0.95 and 6.99 to 3.55 V µ-b;m⁻¹, respectively, while the emission current density increases significantly from 1.2 to 13.8 mA cm⁻² (at 7.35 V µ-b;m⁻¹) with an increase in the ambient temperature from RT to 623 K. The field enhancement factor, emission current density, and the dependence of the effective work function with temperature are investigated. The possible mechanism of the temperature-dependent emission from PrB₆ nanorods is discussed.