Carbon Nanotube Solar Antenna Array Fabrication
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Solution Overview
Problem
Current manufacturing processes for visible light rectennas are expensive due to the need for deep submicron masking technology, which is costly and inefficient compared to existing semiconductor fabrication capabilities, and existing solar cell arrays have lower efficiency than rectenna arrays.
Innovation Solution
The use of self-aligning process steps and molds made using current IC masking techniques to create carbon nanotube ¼-wavelength antennas connected to power or ground rails via direct metal connections or Metal oxide Carbon (MoC) or Metal insulator insulator Metal (MII) diodes, allowing for the production of randomly placed antennas varying in length from 80 to 620 nanometers, which are attached to a plastic surface with thick film metal lines for energy collection and reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deep submicron masking technology is used to manufacture visible light rectennas, then the required tens of nanometer dimensions can be achieved, but the manufacturing cost increases significantly
Solution Approach 1:
The patent introduces a mold as an intermediary component that pre-defines the antenna patterns. This mold acts as a master template that can be reused multiple times, eliminating the need for expensive deep submicron masking for each fabrication run. The mold contains pre-formed V-grooves and raised portions that directly transfer the antenna geometry to the substrate through simple deposition and release processes.
Solution Approach 2:
The antenna patterns are pre-formed in the mold before the actual fabrication process. The V-grooves and raised portions are created in advance using standard lithography, and then this pre-prepared mold is used to define the antenna locations and geometries during fabrication, avoiding the need for complex real-time patterning at nanometer scales.
2Loss of energy
If microwave rectenna arrays are used, then high conversion efficiency of up to 40% can be achieved, but the technology is not applicable to visible light spectrum
Solution Approach 1:
The patent changes the key parameter of antenna dimension to match the visible light wavelength scale. By reducing antenna dimensions from microwave scales to tens of nanometers and using carbon nanotubes with appropriate electrical properties, the system achieves high efficiency rectification specifically optimized for visible light frequencies while maintaining the fundamental rectenna operating principle.
Solution Approach 2:
The patent employs carbon nanotubes as the antenna material, combining the properties of metallic conductivity with nanoscale dimensions. This composite approach allows the antennas to function efficiently at visible light frequencies while maintaining the rectifying functionality needed for high energy conversion efficiency.
3Ease of manufacture
If standard solar cell processes are used, then large dimension requirements are met, but the conversion efficiency is lower than rectenna arrays
Solution Approach 1:
The patent divides the solar energy conversion function into discrete antenna elements arranged in arrays. Each antenna acts as an independent rectifying unit that converts electromagnetic energy to electrical current. This segmented approach allows for scalable manufacturing using standard processes while achieving higher efficiency through the rectenna mechanism rather than traditional photovoltaic junctions.
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
This approach enables the economical production of efficient solar energy conversion devices that utilize existing semiconductor fabrication capabilities, achieving high efficiency in converting visible light to electricity while reducing manufacturing costs.
Implementation Method 1
The antennas may be of varied length, with variances and means adjusted for the environment in which they may be used. An optimal collector may consist of randomly placed 1⁄4-wavelength antennas that may vary from 80 nanometers to 620 nanometers in length.
Implementation Method 2
carbon nanotubes may be grown between the power and ground lines. In one embodiment the carbon nanotubes may be grown off of a nickel ball that may be electrically connected to the ground lines
Implementation Method 3
The antenna array may be attached to a plastic surface, which may include a large percentage of thick film metal lines for both collecting the electrical energy and reflecting the light back to the array.
Implementation Method 4
The vias may be burned by a laser. The laser may be broadcast through a mask.
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
A solar antenna array may comprise an array of randomly placed carbon nanotube antennas that may capture and convert sunlight into electrical power. Methods for constructing the solar antenna array may use a mold and self aligning processing steps to minimize cost. Designs may be optimized for capturing a broad spectrum of non-polarized light. Alternatively, the array may generate light, and when connected in to an array of independently controllable sections may operate as either a reflective or light transmitting display.