HfC Nanowire Emitter Coating for Stable Single-Spot 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 (HfC 1-x O x) is developed, where the thickness of the hafnium oxycarbide is between 1 nm and 20 nm, and the end has a tapered shape with a specific radius of curvature, enhancing electron emission stability and efficiency.
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 stability of electron emission characteristics deteriorates
Solution Approach 1:
The invention uses a composite structure consisting of a hafnium carbide single crystal nanowire core coated with a hafnium oxide layer. This composite material approach combines the high electron emission efficiency of HfC with the stability and protective properties of HfO2, resolving the contradiction between emission efficiency and stability.
Solution Approach 2:
The invention applies local quality modification by coating only the surface of the hafnium carbide nanowire with hafnium oxide, while maintaining the single crystal structure and properties of the core. This allows the core to provide high emission efficiency while the surface coating provides stability.
2Productivity
If the tip of the emitter is sharpened to generate electric field concentrating effect, then electron emission is improved, but manufacturing precision requirements increase
Solution Approach 1:
The invention optimizes the geometric parameters of the nanowire tip, specifically controlling the radius of curvature to be 5-50 nm and the aspect ratio (length/diameter) to be 5-100. These parameter ranges achieve effective field concentration while being manufacturable through controlled growth processes.
Solution Approach 2:
The invention utilizes a controlled curvature at the nanowire tip rather than an infinitely sharp point. The specified radius of curvature range (5-50 nm) provides sufficient field concentration effect while being physically realizable and stable, avoiding the manufacturing precision issues associated with ultra-sharp tips.
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 a single-spot field electron emission pattern with improved stability and efficiency, reducing the work function and enabling long-term stable electron emission.
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
at least an end of the nanowire, through which electrons are to be emitted, is coated with hafnium oxycarbide (HfC 1-x O x : 0
Data Source
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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.