Study on Pyramidal Molybdenum Nanostructures Cold Cathode with Large-Current Properties Based on Self-Assembly Growth...

In order to develop a field emission cold cathode for power vacuum electronic device applications, it is important to realize the properties of large-current and high current density. This requires the design and preparation of cold cathode materials with good crystallization, suitable geometric structure, and good contact interface. In this study, we report a pyramidal molybdenum nanostructure with single crystalline nature, which was self-assembly grown by a thermal evaporation method. We also report the optimization of the nanostructure, successfully sharpening its top end and reducing the thickness of the intermediate layer between the structure and the substrate (from 31.4 to 3.1 nm). By this way, the pyramidal molybdenum nanostructure exhibits high conductivity of about 1.8 × 10⁵ Ω^-1 cm^-1. The cold cathode composed by these nanostructures shows a large-current field emission performance, with the largest emission current of 47.62 mA as well as the highest current density of 2.38 A cm^-2, under a pulsed electric field as high as 28 V μm^-1. The proposed pyramidal molybdenum nanostructures provide a candidate for the large-current cold cathode of the power electronic devices.