CVD Diamond NV Center Formation via Controlled Irradiation and Annealing
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Solution Overview
Problem
Current methods for producing fancy colored diamonds and materials suitable for spintronic applications face challenges in maximizing NV centers while minimizing other defects, particularly in CVD diamond materials, where achieving high densities of NV centers with low densities of other defects is difficult, and existing techniques often result in brown coloration due to nitrogen defects.
Innovation Solution
A method involving irradiation and annealing of CVD diamond material with single substitutional nitrogen (N s 0<) to introduce isolated vacancies and form NV centers, optimizing the concentration of N s 0< defects to achieve fancy pale pink coloration and enhanced spintronic properties, while minimizing brown coloration and other defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If irradiation and annealing is applied to CVD diamond material to form NV centers, then NV center density is improved, but brown coloration due to nitrogen defects increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the annealing temperature (700-900°C) and duration (0.1-10 hours) to optimize NV center formation while minimizing brown coloration. It also controls the irradiation dose to create isolated vacancies that combine with nitrogen atoms to form NV centers rather than producing excessive brown coloration from nitrogen defects.
Solution Approach 2:
The patent converts the harmful effect of nitrogen defects (which cause brown coloration) into a beneficial effect by utilizing them as precursors for NV center formation. Through controlled irradiation and annealing, nitrogen atoms combine with vacancies to form NV centers, which are desirable for both optical properties and spintronic applications, thereby transforming the harmful nitrogen presence into a beneficial feature.
2Ease of manufacture
If nitrogen concentration is increased to enhance coloration, then fancy color is improved, but other defects and brown coloration increase
Solution Approach 1:
The patent optimizes the nitrogen concentration parameter to achieve the desired fancy color while controlling other defect densities. By adjusting the nitrogen content in the CVD diamond material and controlling the irradiation and annealing parameters, the patent achieves high NV center density with low densities of other defects, thereby improving both color quality and material reliability.
3Reliability
If high temperature annealing is applied to remove defects, then purity is improved, but NV center formation is reduced
Solution Approach 1:
The patent identifies and resolves this contradiction by optimizing the annealing temperature range (700-900°C) and duration (0.1-10 hours). This parameter optimization allows sufficient thermal energy for vacancy formation and NV center development while preventing excessive defect removal that would reduce NV center concentration. The controlled parameter range enables simultaneous achievement of high NV center density and acceptable material purity.
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 method effectively produces diamond materials with high NV center densities and low densities of other defects, achieving desirable fancy pale pink colors and improved spintronic properties by controlling the concentration of N s 0< defects and annealing conditions.
Implementation Method 1
irradiating the provided CVD diamond material introduces into the material isolated vacancies
Implementation Method 2
annealing the irradiated CVD diamond material creates in the material substitutional nitrogen atoms adjacent to vacancies, that is NV centres
Data Source
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AI summary
A method of introducing NV centres in single crystal CVD diamond material is described. One step of the method comprises irradiating diamond material that contains single substitutional nitrogen to introduce isolated vacancies into the diamond material in a concentration of at least 0.05 ppm and at most 1 ppm. Another step of the method comprises annealing the irradiated diamond to form NV centres from at least some of the single substitutional nitrogen defects and the introduced isolated vacancies. Pink CVD diamond material and CVD diamond material with spintronic properties is also described.