Catalyst Particle Doping for Nanowire Concentration Control
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Solution Overview
Problem
Current methods for doping nanowires and carbon nanotubes face challenges in controlling dopant concentration, particularly achieving low concentrations below 10^17 atoms/cm^3, and ensuring uniform distribution, which affects their integration into electronic devices.
Innovation Solution
The use of catalyst particles comprising a catalyst compound and a dopant element, where the catalyst compound does not significantly dissolve in the nanostructure material, while the dopant element completely dissolves, allowing for controlled dopant concentration and profile along the nanostructure's length, ensuring uniform doping without affecting physical properties like diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If gas-phase dopants are used during nanowire growth, then doping can be achieved, but dopant concentration control is difficult and low concentrations below 10^17 atoms/cm^3 cannot be obtained
Solution Approach 1:
The dopant is pre-introduced into the catalyst particle before nanowire growth begins. This preliminary incorporation allows the dopant to be delivered in a controlled manner during subsequent growth, enabling precise concentration control and uniform distribution throughout the nanowire structure.
Solution Approach 2:
The invention changes the state of the dopant from gaseous (difficult to control) to solid-state incorporation within the catalyst particle. This parameter change enables better control over dopant release and incorporation rates, achieving the desired low concentrations and uniformity.
2Manufacturing precision
If plasma ion implantation is used to dope nanowires, then doping can be achieved, but it is difficult to implant the whole length due to geometry limitations
Solution Approach 1:
The dopant is pre-loaded into the catalyst particle before growth. As the nanowire grows from the catalyst, the dopant is continuously delivered along the entire length of the growing structure, overcoming the geometric limitations of post-growth implantation methods.
Solution Approach 2:
The dopant incorporation occurs continuously during the entire growth process rather than as a discrete post-processing step. This continuous delivery mechanism ensures uniform doping throughout the full length of the nanowire, eliminating the limitations of batch implantation methods.
3Manufacturing precision
If dopant gases are added during vapor phase growth, then doping can be achieved, but catalyst particle deformation occurs affecting nanowire diameter
Solution Approach 1:
The dopant is extracted from the gas phase and incorporated into the solid catalyst particle structure. This separation of dopant delivery from the gas-phase growth environment prevents catalyst deformation while maintaining controlled dopant incorporation during nanowire growth.
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 formation of nanowires with precise dopant concentrations, including low concentrations, and varying profiles, enhancing their integration into electronic devices by maintaining structural integrity and performance.
Implementation Method 1
a catalyst compound for catalyzing growth of an elongated nanostructure
Implementation Method 2
at least one dopant element for doping the elongated nanostructure during growth by substantially completely dissolving in the nanostructure material
Data Source
AI summary
A catalyst particle for use in growth of elongated nanostructures, such as e.g. nanowires, is provided. The catalyst particle comprises a catalyst compound for catalyzing growth of an elongated nanostructure comprising a nanostructure material without substantially dissolving in the nanostructure material and at least one dopant element for doping the elongated nanostructure during growth by substantially completely dissolving in the nanostructure material. A method for forming an elongated nanostructure, e.g. nanowire, on a substrate using the catalyst particle is also provided. The method allows controlling dopant concentration in the elongated nanostructures, e.g. nanowires, and allows elongated nanostructures with a low dopant concentration of lower than 1017 atoms/cm3 to be obtained.