Phosphorus-Doped Diamond NV- Sensor Stability
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Solution Overview
Problem
Conventional diamonds with nitrogen-vacancy centers are not stable in the NV- state, particularly near the surface, resulting in limited decoherence time (T2) of about 1.8 ms at room temperature, which restricts the performance of sensor elements.
Innovation Solution
A sensor element composed of n-type phosphorus-doped diamond with a carbon isotope ratio of 12C exceeding 99% and phosphorus concentration between 1 × 10^15 cm^-3 and 1 × 10^18 cm^-3, which stabilizes NV centers in the NV- state, achieving a decoherence time of over 2.1 ms and enhanced magnetic field sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional diamond is used with nitrogen-vacancy centers, then the sensor element can be manufactured, but the NV centers are unstable in NV- state particularly near the surface, resulting in limited decoherence time
Solution Approach 1:
The patent applies parameter changes by modifying the chemical composition and doping concentration of the diamond. Specifically, it uses n-type phosphorus doping with concentrations between 1×10^15 cm^-3 and 1×10^18 cm^-3, and controls the carbon isotope ratio (12C > 99%) to stabilize NV centers in the NV- state and extend decoherence time beyond 2.1 ms at room temperature.
Solution Approach 2:
The patent employs composite material principles by creating a doped diamond structure with multiple components: phosphorus dopants, nitrogen-vacancy centers, and controlled carbon isotope composition. This composite approach at the atomic level stabilizes the NV- state and enhances quantum coherence properties.
2Duration of action of stationary object
If phosphorus doping is applied to stabilize NV centers, then decoherence time is extended, but the manufacturing process becomes more complex
Solution Approach 1:
The patent applies preliminary action by incorporating phosphorus doping during the diamond growth process itself rather than as a subsequent treatment. The chemical vapor deposition method integrates dopant introduction from the beginning, simplifying the overall manufacturing process while achieving the desired stabilization of NV centers.
Solution Approach 2:
The patent specifies precise parameter ranges for manufacturability: phosphorus concentration between 1×10^15 cm^-3 and 1×10^18 cm^-3, and 12C isotope ratio greater than 99%. These controlled parameters enable reproducible manufacturing with extended decoherence time while managing process complexity.
3Reliability
If high phosphorus concentration is used, then NV- state stability improves, but the diamond structure may be affected
Solution Approach 1:
The patent identifies and controls critical parameter thresholds: phosphorus concentration between 1×10^15 cm^-3 and 1×10^18 cm^-3. This optimized range provides sufficient NV- state stability while maintaining diamond crystal structure integrity, avoiding excessive doping that would compromise structural stability.
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 n-type phosphorus-doped diamond sensor element exhibits superior performance with extended decoherence time and high magnetic field sensitivity, enabling stable operation from extremely low to high temperatures without the need for cooling mechanisms, suitable for various measurement devices including medical and in-vehicle equipment.
Implementation Method 1
n-type phosphorus-doped diamond which stabilizes NV centers in an NV- state
Implementation Method 2
the decoherence time T2 of the nitrogen-vacancy centers is preferably more than 2.1 ms as measured in the condition of 300 K by the Hahn Echo method
Data Source
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AI summary
The present invention provides a sensor element including a diamond in which nitrogen-vacancy centers in a diamond crystal structure stabilize in a negative charge state. By ensuring that the diamond of the sensor element is n-type phosphorus-doped and contains nitrogen-vacancy centers in the crystal structure, the probability that nitrogen-vacancy centers in the diamond lattice are in a neutral state decreases, and the nitrogen-vacancy centers stabilize in a negative charge state.