NV Diamond Plates
The nitrogen-vacancy (NV) center in diamond is used for detection of local magnetic or electric fields and/or temperature. Depending on use case and required sensitivity, different designs of diamond plates containing NV centers can be produced. NVs can be distributed throughout the entire volume of a diamond plate or with preferentially distribution within nano- or micrometer thick layers near diamond surfaces. The nitrogen content in the host diamond sample plays an important role in the NV quantum characteristics. HPHT or CVD synthesized plates containing the lowest concentration of nitrogen (< ~5 ppb) are used to reach ultimate sensitivity and spatial resolution. HPHT synthesized diamond plates containing 100-300 ppm of nitrogen provide affordable solutions for less demanding sensing applications. Adámas currently provides two lines of NV diamond plates products: Type Ib HPHT plates with NVs distributed throughout the entire plate volume and Type II CVD plates or HPHT plates with about 0.5 um NV layer near one of the plate surface. Plates of different sizes are available.
Figure 1. Schematic view of the NV centers distributed within bulk of a plate.
Figure 2. Picture of 3 x 3 x 0.3 mm3 <100> oriented diamond plates containing ca. 2 ppm of NV centers.
Technical Characteristics
Type Ib HPHT Plates, Volume Distributed NVs
Diamond plates with NV centers distributed over the entire volume (Figures 1 and 2) are useful in magnetometry where magnetic field variation happens at a millimeter length scales. Oriented ensembles of NV centers in as large as millimeter sized plates boost signal and increase sensitivity. These plates are also convenient for education in quantum physics and in R&D.
NV concentrations in the Type Ib plates is on the order of 1-2 ppm. The single crystal plates are available with <100> or <111> crystal orientations. <100> orientated plates are available with dimensions of 3 x 3 x 0.3 mm3. <111> oriented plates are macle type cuts, with nominal dimensions of 4 x 4 x 3 mm edge lengths and 1 mm thickness. The <100> plates are available with either one or two side polishes (Table 1).
ODMR spectra and T1 relaxation curves are shown in Figures 3 and 4. Quantum characteristics are summarized in Table 2.
Diamond plates annealed at high temperature (1600°C) with improved quantum characteristics are available upon request.
Type II HPHT and CVD Plates with micro- shallow NV centers
Plates with micron shallow NV layers (Fig. 5) are tailored for magnetometry applications where microscale spatial resolution and sensitivity are needed. These plates can be suitable for scanning magnetometry or microscale nuclear magnetic resonance (NMR).
Adámas provides plates with NV centers generated in either HPHT (N < ~ 10 ppb) or CVD synthesized diamond plates with <100> crystal orientation. The CVD plates are either electronic grade (EG) (N < 5 ppb) or optical grade (OG) (N<1 ppm). A variety of plate dimensions are available. Typical characteristics are summarized in Table 3.
Figure 3: Typical ODMR spectra for plates with volume distributed NVs with fit of two summed Lorentzians
Figure 4: Typical T1 relaxation curve for plates with volume distributed NVs with stretched exponential fit.
Figure 5: Schematic view of the NV centers distributed within ~0.5 um top layer of a plate
Relevant Tables
| Dimensions (mm) | Type | Orientation | NV (ppm) | Surface Finish, Ra |
|---|---|---|---|---|
| 3 x 3 x 3 | HPHT, Ib | <100> | 1.5 | Side 1: <30nm, Side 2 <250 nm |
| 3 x 3 x 0.3 | HPHT, Ib | <100> | 1.5 | Side 1: <30 nm, Side 2: <5 nm |
| 4 x 4 x 3 x 1* | HPHT, Ib | <111> | 1.5 | <500 nm on {111} face |
Table 1. Physical characteristics of single crystal diamonds with NV centers distributed through entire volume of the plate. *<111> Macle plates have two edge lengths (4 and 3 mm) and 1 mm thickness.
Table 2. Ensemble NV spin characteristics of plates with volume distributed NVs.
Table 3. Physical characteristics of plates with micro shallow (~0.5 µm) NV center layers