Carbon Nanotube Field Emitter Adhesive Bonding and Laser Tip Exposure
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Solution Overview
Problem
Carbon nanotube field emission devices face issues with poor electrical contact and instability due to the carbon nanotubes not being securely attached to the substrate, leading to non-uniform and unstable electron emission.
Innovation Solution
A method involving the application of an adhesive to secure carbon nanotubes on the substrate and subsequent laser treatment to expose their tips, ensuring better electrical connection and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If carbon nanotubes are grown on substrate by chemical vapor deposition, then good electrical contact with substrate is achieved, but carbon nanotubes are not secured on substrate and are apt to be pulled out by electric field force
Solution Approach 1:
The patent introduces an adhesive layer as an intermediary substance between the carbon nanotubes and the substrate. This adhesive mediator provides both mechanical anchoring to secure the nanotubes against electric field forces and maintains electrical conductivity to preserve good electrical contact. The adhesive acts as a bridge that simultaneously addresses both the attachment stability and electrical contact quality requirements.
2Ease of manufacture
If carbon nanotubes are mixed in plasma and printed on substrate, then printing process is simple, but electrical contact between carbon nanotubes and substrate is bad resulting in non-uniform and unstable electron emission
Solution Approach 1:
The adhesive layer serves as a mediator that improves electrical contact between the printed carbon nanotubes and the substrate. By introducing this intermediate bonding layer, the patent maintains the simplicity of the printing process while resolving the electrical contact issue, enabling uniform and stable electron emission.
Solution Approach 2:
The patent changes the electrical contact parameter by introducing the adhesive layer, which modifies the interface properties between carbon nanotubes and substrate. This parameter change transforms the poor electrical contact state into a good electrical contact state, enabling reliable electron emission while keeping the manufacturing process simple.
3Stability of the object's composition
If adhesive is applied to secure carbon nanotubes on substrate, then carbon nanotubes are secured and electrical contact is improved, but adhesive at surface causes shielding between adjacent carbon nanotubes
Solution Approach 1:
The patent removes the adhesive from the surface where it would cause shielding between carbon nanotubes. By extracting the harmful adhesive material from the emission-critical surface region, the patent eliminates the shielding effect while preserving the adhesive's beneficial securing function at the interface between nanotubes and substrate.
Solution Approach 2:
The patent applies different quality requirements to different regions: the adhesive is present at the substrate interface for secure attachment but absent from the surface region to avoid shielding. This local differentiation of adhesive presence optimizes both attachment stability and electron emission performance by addressing the specific needs of each region.
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 solution secures carbon nanotubes to the substrate, preventing detachment under strong electric fields and enhances electron emission by reducing shielding and threshold voltage, resulting in stable and uniform electron emission with increased field emission current.
Implementation Method 1
an adhesive is applied to secure the carbon nanotubes on the substrate
Implementation Method 2
treating surfaces of the carbon nanotube array by laser
Implementation Method 3
carbon nanotubes typically have superior performance; in particular, good electron emission capability at low emission voltages, generally less than 100 volts
Data Source
AI summary
A carbon nanotube field emission device (100) includes a substrate (10), and a carbon nanotube array (30) formed on and secured to the substrate. This avoids separation of the carbon nanotubes from the substrate by electric field force in a strong electric field. Tips of the carbon nanotubes are exposed. A method for manufacturing the carbon nanotube field emission device includes the steps of: (a) depositing a catalyst film (20) on a substrate; (b) forming a carbon nanotube array on the substrate; (c) injecting an adhesive into the carbon nanotube array, and drying the adhesive; and (d) treating surfaces of the carbon nanotube array by laser. The carbon nanotube field emission device has reduced shielding between adjacent carbon nanotubes, reduced threshold voltage, and increased field emission current.