HfC Nanowire Emitter Tip Coating for Stable Electron Emission
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Solution Overview
Problem
Hafnium carbide single crystal nanowire emitters suffer from instability in electron emission characteristics, limiting their efficiency and stability compared to conventional emitters.
Innovation Solution
A hafnium carbide single crystal nanowire emitter with an end coated with hafnium oxycarbide (HfC1-xOx: 0<x≤0.5) is developed, reducing the work function and enhancing stability through field evaporation and oxidation processes, resulting in a single-spot field electron emission pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a hafnium carbide single crystal nanowire is used as an emitter, then electron emission efficiency is improved, but emission stability deteriorates
Solution Approach 1:
The patent applies composite materials by coating the hafnium carbide single crystal nanowire with hafnium oxide, creating a composite structure that combines the high electron emission efficiency of HfC with the stability and protective properties of HfO2. This composite approach resolves the contradiction by allowing the core material to provide emission efficiency while the coating layer provides stability.
Solution Approach 2:
The patent applies local quality by selectively coating only the tip region of the nanowire with hafnium oxide, rather than the entire structure. This localized coating approach maintains the excellent electron emission properties of the HfC single crystal while providing stability enhancement only where needed at the emission surface.
2Productivity
If the nanowire tip is sharpened to generate electric field concentrating effect, then electron emission is enhanced, but structural stability deteriorates
Solution Approach 1:
The patent applies beforehand cushioning by pre-coating the nanowire tip with hafnium oxide before use, creating a protective layer that cushions and protects the sharp tip structure. This coating prevents structural degradation while maintaining the electric field concentrating effect needed for enhanced electron emission.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The emitter achieves stable and efficient electron emission with improved work function reduction and prolonged emission stability, suitable for high-performance electron guns in microscopes and spectrometers.
Implementation Method 1
these are characterized in that the tip of an emitter used in an electron gun is sharpened to generate an electric field concentrating effect at the tip and to emit more electrons through the tip
Implementation Method 2
subjecting a nanowire made of a hafnium carbide single crystal to field evaporation in atmospheric gas, forming an end of the nanowire, through which electrons are to be emitted, into a tapered shape
Implementation Method 3
heating the nanowire in an oxygen-containing atmosphere. In the method, the length d of the nanowire in the lateral direction is 150 nm or less, and in the heating the nanowire, an oxygen partial pressure is in a range of 1×10−8 Pa or more and 1×10−5 Pa or less
Data Source
AI summary
The present invention provides an emitter made of a hafnium carbide (HfC) single crystal that stably emits electrons with high efficiency, a method for manufacturing the emitter, and an electron gun and an electronic device using the emitter. An emitter according to an embodiment of the present invention is an emitter including a nanowire, in which the nanowire is made of the hafnium carbide (HfC) single crystal, at least an end of the nanowire through which electrons are to be emitted is coated with hafnium oxycarbide (HfC1-xOx: 0<x≤0.5), and a field electron emission pattern of the end obtained by a field emission microscope (FEM) is a single spot.