A Mo nanoscrew formed by crystalline Mo grains with high conductivity and excellent field emission properties

Abstract

A novel screw-like molybdenum nanostructure has been synthesized based on a simple thermal vapor deposition method. Each thread circle of the nanoscrews is formed by several crystalline Mo grains, which have a certain deflection with each other. The growth mechanism is described as a spiral growth mode, which depends heavily on the degree of supersaturation (σ) of deposited Mo vapors. The electrical property measurements and field emission properties on a single Mo nanoscrew show that their electrical conductivity should reach 3.44 × 10⁴–7.74 × 10⁴ Ω⁻¹ cm⁻¹ and its maximum current should reach 15.8 μA. Mo nanoscrew film is also proved to have excellent field emission properties in different voltage driver modes. The largest emission current densities can reach 106.39 mA cm⁻² in the DC voltage driver mode and 0.66 A cm⁻² in the pulsed mode. A low turn-on field, good site distribution and remarkable emission stability is also recorded. These experimental results show that the highly conductive molybdenum nanoscrews should have potential applications as a cold cathode material for high current vacuum electron devices.