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High-sensitivity temperature sensing using an implanted single nitrogen-vacancy center array in diamond

MetadataDetails
Publication Date2015-04-06
JournalPhysical Review B
AuthorsJunfeng Wang, Fupan Feng, Jian Zhang, Jihong Chen, Zhongcheng Zheng
InstitutionsWuhan University, Hefei National Center for Physical Sciences at Nanoscale
Citations97
AnalysisFull AI Review Included

Technical Documentation & Analysis: High-Sensitivity NV Center Thermometry

Section titled “Technical Documentation & Analysis: High-Sensitivity NV Center Thermometry”

This document analyzes the research demonstrating high-sensitivity nanoscale thermometry using implanted Nitrogen-Vacancy (NV) centers in high-purity diamond. The findings validate the critical role of high-quality Single Crystal Diamond (SCD) substrates in achieving advanced quantum sensing performance.

  • Core Achievement: Demonstrated high-sensitivity temperature detection using implanted single NV center arrays in diamond via the high-order Thermal Carr-Purcell-Meiboom-Gill (TCPMG) method.
  • Coherence Extension: The TCPMG-8 sequence extended the spin coherence time (TD) for thermometry up to 108 ”s, a 14-fold improvement over the Thermal Ramsey method (7.7 ”s).
  • Thermal Sensitivity: Achieved a thermal sensitivity (η) of 10.1 mK/Hz1/2, comparable to results obtained using native NV centers in isotopically pure diamond.
  • Material Requirement: The experiment relied on ultra-high-purity, electronic-grade Single Crystal Diamond (SCD) with ultra-low nitrogen concentration ([N] < 5 ppb) to minimize spin bath noise.
  • Application Potential: The results pave the way for utilizing implanted NV centers in high-quality diamond for high-resolution temperature mapping in microelectronic systems, chemistry, and biological sensing.
  • 6CCVD Value Proposition: 6CCVD specializes in providing the necessary low-strain, ultra-low nitrogen SCD substrates, custom dimensions, and advanced polishing (Ra < 1 nm) required for successful shallow ion implantation and subsequent quantum device fabrication.

The following hard data points were extracted from the research paper, highlighting the critical material and performance metrics achieved.

ParameterValueUnitContext
Substrate MaterialSCDN/AHigh-quality electronic grade diamond
Substrate Dimensions2 x 2 x 0.5mm3Used for NV array implantation
Crystal Orientation(100)N/ARequired for device fabrication
Nitrogen Concentration ([N])< 5ppbUltra-low impurity requirement
Implantation Species14N+N/ASource for NV center creation
Implantation Energy60keVDetermines NV depth profile
Implantation Fluence2.25 x 101114N/cm2Dose used for NV array
Average Implantation Depth~40nmShallow NV centers for surface sensing
Annealing Temperature1050°CVacuum annealing for vacancy diffusion
Maximum Coherence Time (TD)108”sAchieved using TCPMG-8 sequence
Best Thermal Sensitivity (η)10.1mK/Hz1/2Comparable to isotopically pure diamond
Measured Thermal Sensitivity (η)24mK/Hz1/2Achieved using TCPMG-3 sequence
Diamond Thermal Conductivity (k)~2000W/mKHigh thermal dissipation property

The successful creation of high-performance implanted NV centers requires precise control over material growth, surface preparation, and post-processing.

  1. Substrate Selection: Utilization of ultra-high-purity Single Crystal Diamond (SCD) with < 5 ppb nitrogen concentration and (100) orientation to minimize intrinsic spin defects and maximize coherence time.
  2. Surface Preparation: Preparation of the diamond surface for electron beam lithography (EBL) masking, requiring ultra-smooth polishing (Ra < 1 nm compatibility).
  3. Masking and Implantation: EBL patterning of a PMMA mask with 45 nm diameter apertures, followed by 60 keV 14N+ ion implantation at a 7° angle to create shallow NV precursors (~40 nm depth).
  4. NV Formation (Annealing): High-temperature annealing at 1050 °C in a high vacuum (2 x 10-5 Pa) for 2 hours to mobilize carbon vacancies, allowing them to pair with implanted nitrogen atoms to form NV centers.
  5. Charge State Optimization: Oxidation at 430 °C in atmosphere for 2.5 hours, followed by cleaning in a boiling acid mixture (sulfuric, nitric, perchloric acid) at 200 °C to improve the conversion efficiency to the negatively charged NV- state.
  6. Quantum Sensing: Application of high-order pulse sequences (TCPMG-N) in a static magnetic field to extend the spin coherence time, enabling high-sensitivity measurement of the temperature-dependent zero-field splitting (D).

6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials and customization services necessary to replicate and extend this high-sensitivity quantum thermometry research.

The success of this experiment hinges on the quality of the starting material, specifically its purity and crystalline perfection.

  • Electronic Grade Single Crystal Diamond (SCD):
    • Requirement Match: The paper used SCD with [N] < 5 ppb. 6CCVD provides ultra-low nitrogen SCD essential for minimizing the electron spin bath noise (P1 centers) that limits T2 and thermal sensitivity.
    • Performance Extension: For next-generation devices aiming for submK/Hz1/2 sensitivity, 6CCVD offers Isotopically Purified SCD (12C > 99.99%). Reducing the natural 1.1% 13C concentration eliminates the dominant nuclear spin bath, leading to millisecond-scale coherence times (T2) and vastly improved sensor performance.

6CCVD’s in-house engineering capabilities directly address the fabrication challenges inherent in creating NV center arrays.

Requirement from Paper6CCVD CapabilityTechnical Specification
Substrate Size/ThicknessCustom Dimensions & SubstratesSCD substrates available up to 10 mm thick. SCD plates available from 0.1 ”m to 500 ”m.
Surface QualityUltra-Smooth PolishingSCD surfaces polished to Ra < 1 nm, ideal for high-resolution EBL masking and shallow implantation uniformity.
Implantation CompatibilityCustom Thickness ControlPrecise control over SCD thickness (e.g., 0.5 mm used in the paper) ensures optimal thermal management (k ~2000 W/mK) for integrated devices.
Integrated Device FabricationCustom MetalizationInternal capability to deposit thin films (Au, Pt, Pd, Ti, W, Cu) for integrated microwave antennas (like the copper wire used) or heating elements directly onto the diamond surface.
Large-Area ScalingPCD WafersFor scaling up quantum sensor production, 6CCVD offers Polycrystalline Diamond (PCD) wafers up to 125 mm in diameter, polished to Ra < 5 nm.

6CCVD’s technical sales team and in-house PhD material scientists provide authoritative support for complex quantum projects.

  • Material Optimization: Our team assists researchers in selecting the optimal SCD grade, orientation, and thickness to balance coherence time requirements with thermal management needs for Nanoscale Quantum Thermometry projects.
  • Process Consultation: We offer guidance on pre-implantation surface termination and post-growth annealing strategies to maximize NV- conversion efficiency and minimize surface defects, crucial steps detailed in the paper (1050 °C vacuum anneal, 430 °C oxidation).

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

We presented a high-sensitivity temperature detection using an implanted single Nitrogen-Vacancy center array in diamond. The high-order Thermal Carr-Purcell-Meiboom-Gill (TCPMG) method was performed on the implanted single nitrogen vacancy (NV) center in diamond in a static magnetic field. We demonstrated that under small detunings for the two driving microwave frequencies, the oscillation frequency of the induced fluorescence of the NV center equals approximately to the average of the detunings of the two driving fields. On basis of the conclusion, the zero-field splitting D for the NV center and the corresponding temperature could be determined. The experiment showed that the coherence time for the high-order TCPMG was effectively extended, particularly up to 108 {\mu}s for TCPMG-8, about 14 times of the value 7.7 {\mu}s for thermal Ramsey method. This coherence time corresponded to a thermal sensitivity of 10.1 mK/Hz1/2. We also detected the temperature distribution on the surface of a diamond chip in three different circumstances by using the implanted NV center array with the TCPMG-3 method. The experiment implies the feasibility for using implanted NV centers in high-quality diamonds to detect temperatures in biology, chemistry, material science and microelectronic system with high-sensitivity and nanoscale resolution.