Sensor Device

Abstract

The sensor device includes a first sensing surface area and a second sensing surface area, the first sensing surface area and the second sensing surface area being located on a diamond material. The first sensing surface area is within an interaction distance of a first at least one spin defect, and the second sensing surface area is within an interaction distance of a second at least one spin defect, the spin defect being located in the diamond material. Also provided is a magnetic excitation source configured to provide a bias magnetic field, a light source configured to excite charge carriers in a conduction band, and a current detector configured to detect charge carriers excited from one or more spin defects proximate at least one of the sensing surface areas. The first and second sensing surface areas are optimized for different sensing purposes.

Description

[Technical field]

[0001] The present invention relates to the field of sensor devices, particularly sensor devices formed from diamond material, and also to methods of forming and using such sensor devices. [Background technology]

[0002] Point defects, in particular quantum spin defects and / or optically active defects, in synthetic diamond material have been proposed for use in a variety of imaging, sensing and processing applications including, for example, luminescence tags, magnetometers, spin resonance instruments such as Nuclear Magnetic Resonance (NMR) and Electron Spin Resonance (ESR) instruments, spin resonance imaging devices for Magnetic Resonance Imaging (MRI), quantum information processing instruments such as quantum communication and quantum computing, magnetic communication devices, and gyroscopes.

[0003] Certain defects have been found to be particularly useful for sensing or quantum processing applications. For example, negatively charged nitrogen-vacancy defects (NV vacancies) in synthetic diamond material. - ) has attracted much interest as a useful quantum spin defect because it has several desirable features, including: (i) its electron spin state can be coherently manipulated with high fidelity and has extremely long coherence times (this is known as the transverse relaxation time, T 2 and / or T 2* can be used to quantify and compare. (ii) Their electronic structure allows defects to be optically pumped to their electronic ground state, placing such defects in specific electronic spin states without the need for cryogenic temperatures. This feature can eliminate the requirement for expensive and bulky cryogenic cooling equipment for certain applications where miniaturization is desirable. Furthermore, defects can act as a source of photons that all have the same spin state. (iii) Its electronic structure contains emissive and non-emissive electron spin states, which allows the readout of the defect's electron and spin states through photons. This feature is favorable for reading out information from synthetic diamond materials for use in sensing applications such as magnetometry, spin resonance spectroscopy and imaging. Moreover, this feature is also a key ingredient for using NV defects as qubits for long-distance quantum communication and scalable quantum computing. These results suggest that NV defects are a promising candidate for a novel quantum-mechanical defect. - Defects have become attractive candidates for solid-state quantum information processing (QIP).

[0004] Diamond NV - The defect consists of a substitutional nitrogen atom adjacent to a carbon vacancy. Its two unpaired electrons are in the electronic ground state ( 3 A) forms a spin triplet, with the degenerate ms=±1 sublevels 2.87 GHz away from the ms=0 level. NV - The electronic structure of the defect is such that the ms=0 sublevel exhibits a high fluorescence rate when photoexcited. In contrast, when the defect is excited in the ms=±1 levels, it emits a non-radiative singlet state ( 1 A) has a high probability of relaxing to the ms=0 level after crossing over to the ms=0 level. As a result, the spin state can be read out optically, with the ms=0 state being "bright" and the ms=±1 states being "dark". When an external magnetic or distorting field is applied, the degeneracy of the spin sublevels ms=±1 is lifted, in the case of a magnetic field this is done via a Zeeman interaction. This leads to a splitting of the resonance lines depending on the magnitude and direction of the applied magnetic / distorting field. This dependence can be used for magnetic measurements by using microwaves (MW) to probe the resonant spin transitions and optically detected magnetic resonance (ODMR) spectroscopy to measure the magnitude and optionally the direction of the applied magnetic field.

[0005] NV − defects in synthetic diamond material can be formed in a number of different ways, including: (i) The formation during growth of synthetic diamond material whereby nitrogen atoms and vacancies are incorporated into the crystal lattice as nitrogen-vacancy pairs; (ii) post-synthesis formation of diamond material from native nitrogen and vacancy defects incorporated during the growth process by post-growth annealing the material at a temperature (around 800°C) at which the vacancy defects migrate through the crystal lattice and pair with native single substitutional nitrogen defects; (iii) post-synthesis formation of diamond material from natural nitrogen defects introduced during the growth process by irradiating the synthetic diamond material with radiation to introduce vacancy defects and then annealing the material at a temperature at which the vacancy defects migrate through the crystal lattice and pair with natural single substitutional nitrogen defects; (iv) formation after synthesis of the diamond material by implanting nitrogen defects into the synthetic diamond material after synthesis of the diamond material and then annealing the material at a temperature at which native vacancy defects migrate through the crystal lattice to pair with the implanted single substitutional nitrogen defects; and (v) Formation after synthesis of a diamond material by irradiating the synthetic diamond material with radiation to introduce vacancy defects, implanting nitrogen defects into the synthetic diamond material either before or after irradiation, and annealing the material at a temperature at which the native vacancy defects migrate through the crystal lattice to pair with the implanted single substitutional nitrogen defects.

[0006] The prior art discloses various different types of diamond materials for use in various different types of magnetometry applications, such as WO 2010 / 010352 and WO 2010 / 010344 which disclose low nitrogen content single crystal chemical vapour deposition (CVD) diamond material for applications such as magnetometry, and WO 2010 / 149775 which discloses irradiated and annealed single crystal CVD diamond material for applications such as magnetometry.

[0007] As an alternative to ODMR, Photoelectric Detection of Magnetic Resonance (PDMR) has been proposed. In PDMR, the spin state of spin defects in the diamond lattice can be directly measured photoelectrically based on the detection of charge carriers generated by excited spin centers. This technique is described in Bourgeois, E. et al., "Photoelectric detection of electron spin resonance of nitrogen-vacancy centers in diamond," Nature Communications, 6, 2015, and in U.S. Patent No. 10,274,551.

[0008] PDMR exploits the change in spin defect photocurrent intensity upon magnetic resonance. The advantages of PDMR are that it is easier to integrate with electronic systems than ODMR, it has faster recombination rates resulting in improved detection rate, and it has a quadratic power dependence of the photocurrent resulting in improved resolution. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2010 / 010352 [Patent Document 2] International Publication No. 2010 / 010344 [Patent Document 3] International Publication No. 2010 / 149775 [Patent Document 4] U.S. Patent No. 10,274,551 [Patent Document 5] International Publication No. 2020 / 201211 [Patent Document 6] International Publication No. 2001 / 096634 [Non-patent literature]

[0010] [Non-Patent Document 1] Bourgeois, E. et al., "Photoelectric detection of electron spin resonance of nitrogen-vacancy centres in diamond", Nature Communications, 6, 2015. [Non-Patent Document 2] Bishop et al., "Deterministic nanopatterning of diamond using electron beams," ACS Nano 2018, 12, 3, 2873-2882 [Non-Patent Document 3] Toros et al., "Reactive ion etching of single crystal diamond by inductively coupled plasma: State of the art and catalog of recipes," Diamond and Related Materials 108, 107839, 10.1016 / j.diamond.2020.107839 [Non-Patent Document 4] Wannemacher et al., "Generation and detection of fluorescent color centers in diamond with submicron resolution," App Phys Lett, 75(20), 3096-3098 Summary of the Invention [Problem to be solved by the invention]

[0011] It is an object of the present invention to provide a diamond sensor device that addresses a problem associated with ODMR that limits the ability to efficiently address individual NV-containing regions of a diamond sensor or single spin defects within the diamond. [Means for solving the problem]

[0012] According to a first aspect, a sensor device is provided that includes a first sensing surface area and a second sensing surface area. The first sensing surface area and the second sensing surface area are located on a diamond material. The first sensing surface area is within an interaction distance of a first at least one spin defect, and the second sensing surface area is within an interaction distance of a second at least one spin defect, the spin defects being located in the diamond material. Also provided is a magnetic excitation source configured to provide a bias magnetic field, a light source configured to excite charge carriers in a conduction band, and a current detector configured to detect charge carriers excited from one or more spin defects proximate at least one of the sensing surface areas. The first and second sensing surface areas are optimized for different sensing purposes.

[0013] Optionally, the first sensing surface area and the second sensing surface area are located on a surface of a single diamond material. Alternatively, the first sensing area is located on a surface of the first diamond material and the second sensing area is located on a surface of a second diamond material.

[0014] Optionally, any of the first and second at least one spin defect is selected from any of a negatively charged nitrogen vacancy center, a silicon vacancy center, a tin vacancy center, a germanium vacancy center, a nickel-related defect, and a chromium-related defect. As a further option, any of the first and second at least one spin defect comprises a single negatively charged nitrogen vacancy center.

[0015] The diamond material optionally includes any of chemical vapor deposition (CVD) diamond material, natural diamond, and high pressure high temperature (HPHT) diamond material.

[0016] A concentration of spin defects proximate the first sensing surface area is optionally different from a concentration of spin defects proximate the second sensing surface area.

[0017] Optionally, either the first or second sensing surface area includes a surface pattern.

[0018] Optionally, either the first or second sensing surface areas include a metal coating that forms an electrical contact.

[0019] Optionally, the sensing objective is selected from among nuclear magnetic resonance, magnetometry, and radio frequency spectroscopy.

[0020] Optionally, either the first or second sensing surface area is in contact with at least one microfluidic channel.

[0021] Optionally, either the first and second sensing areas have a maximum linear dimension selected from: 5000 μm or less, 1000 μm or less, 100 μm or less, 50 μm or less, 10 μm or less, and 1 μm or less.

[0022] Optionally, the sensor device further comprises a microwave source configured to control the spin defects.

[0023] According to a second aspect, there is provided a method of forming a sensor device, comprising providing a first sensing surface area and providing a second sensing surface area, the first and second sensing surface areas being located on a diamond material, the first sensing surface area being within an interaction distance of a first at least one spin defect, and the second sensing surface area being within an interaction distance of a second at least one spin defect. The method further comprises providing a magnetic excitation source configured to provide a bias magnetic field, providing a light source configured to excite charge carriers in a conduction band, and providing a current detector configured to detect charge carriers excited from one or more spin defects proximate at least one of the sensing surface areas. The first and second sensing surface areas are optimized for different sensing purposes.

[0024] Optionally, the method includes providing both the first sensing surface area and the second sensing surface area on a surface of a single diamond material. Alternatively, the method includes providing the first sensing surface area on a surface of a first diamond material and the second sensing surface area on a surface of a second diamond material.

[0025] Optionally, any of the first and second at least one spin defects is selected from any of a negatively charged nitrogen vacancy center, a silicon vacancy center, a tin vacancy center, a germanium vacancy center, a nickel-related defect, and a chromium-related defect.

[0026] Optionally, a concentration of spin defects proximate the first sensing surface area differs from a concentration of spin defects proximate the second sensing surface area.

[0027] The at least one first and second spin defects are optionally provided by doping the diamond during growth, by ion implantation, by annealing the diamond material, and by irradiating the diamond material.

[0028] The method optionally further comprises providing a surface pattern on either the first or second sensing surface area.

[0029] Optionally, the method further includes applying a metal coating to either the first or second sensing surface areas to form an electrical contact.

[0030] According to a third aspect, there is provided a method of using a sensor device as described above in the first aspect, the method comprising positioning the sensor device such that the first and second sensing surface areas are proximate to a substance to be analysed, obtaining a first measurement from the first at least one spin defect, and obtaining a second measurement from the second at least one spin defect.

[0031] The PDMR allows for simpler and more compact interfacing with electronic circuits. Combining the PDMR with the sensor device described above allows efficient and precise individual addressing of different regions of the diamond sensor device. This allows a single sensor to be used to perform different types of analyses on a single sample.

[0032] Non-limiting embodiments will now be described by way of example with reference to the accompanying drawings, in which: [Brief description of the drawings]

[0033] [Figure 1] 1 is a schematic cross-sectional side view of an exemplary sensor device. [Diagram 2] FIG. 2 is a schematic cross-sectional side view of a second exemplary sensor device. [Diagram 3] FIG. 11 is a schematic cross-sectional side view of a third exemplary sensor device. [Figure 4] FIG. 1 is a flow diagram illustrating an exemplary method for manufacturing a sensor device. [Diagram 5] FIG. 2 shows a schematic diagram of a further exemplary sensor device; [Figure 6] FIG. 1 is a flow diagram illustrating an exemplary method of using a sensor device as described herein. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0034] The following description refers to sensors formed from diamond that includes at least one spin center. For convenience, an exemplary spin center is referred to herein as a negatively charged nitrogen vacancy center (NV - ), however, it is known that a variety of spin centers can form in diamond. These include silicon-vacancy centers, tin-vacancy centers, germanium-vacancy centers, nickel-related defects, and chromium-related defects. Those skilled in the art will appreciate that the structures and methods described herein apply to all types of spin centers that may be used in diamond sensors.

[0035] As mentioned above, the complex optical setup associated with ODMR measurements limits the ability to efficiently address independent spin defect-containing regions and single NV centers in diamond sensors. PDMR allows for simpler and more compact interfacing with electronic circuits. It has been shown that combining PDMR with patterning methods allows for efficient and precise addressing of different sensor regions. This allows for multiple types of analysis to be performed on a single sample using a single sensor device.

[0036] NV centers in diamond have been shown to be useful for several different applications, such as magnetic sensing, radio frequency (RF) sensing, and quantum information processing (QIP).

[0037] The inventors have developed a device with multiple sensing regions that individually interact with the electronics best suited for the sensing mode. These regions can be selectively addressed (separately or simultaneously) to provide measurements on different samples or samples that reside on or pass through different regions. Typically, different regions of the sensor can have different concentrations of spin defects, such as NV centers, that are compatible with different sensitivity ranges, different sensing modes (e.g., NMR, magnetometry, hyperpolarized magnetometry, and RF spectroscopy). Additionally or alternatively, different regions of the sensing device can have different surface patterning or coatings to optimize the type of sensing to be performed.

[0038] A sensor device is shown as an example in Fig. 1. In this example, a diamond sensor device 1 is provided having a first sensing surface area 2 and a second sensing surface area 3. The first sensing surface area 2 is within an interaction distance of a first at least one spin defect 4, and the second sensing surface area 3 is within an interaction distance of a second at least one spin defect 5. The first sensing surface area 2 is optimized for one type of sensing, and the second sensing surface area 3 is optimized for a different type of sensing.

[0039] FIG. 2 shows a second exemplary sensor device 6, in which a first sensing area 7 is above an area of ​​diamond with a high concentration of NV centers and is therefore optimized for sensitivity. A second sensing area 8 is above an area of ​​diamond with a low concentration of NV centers 8 and is therefore optimized for high resolution sensing. A third sensing area 9 is above an area of ​​diamond with a very low concentration of NV centers for nano-NMR applications. In use, the same diamond with different sensing areas 7, 8, 9 can be used to simultaneously perform the above different types of sensing on a liquid sample, with a fluid 10 flowing over it and PDMR being used to query each sensing area 7, 8, 9 individually. Such a sensor device can be used, for example, in a microfluidic channel for proteomics, where the first sensing area 7 is used to detect small magnetic fields, the second sensing area 8 is used to give more accurate information on the size and / or number of proteins detected, and the third sensing area 9 is used to perform nano-NMR on the flowing liquid 10.

[0040] FIG. 3 shows a third exemplary sensor device 11, in which a first sensing area 12 is above a region of diamond material with a concentration of spin defects, and a second sensing area 13 has a surface pattern or coating. For example, the diamond surface can be patterned to enhance nano-NMR capabilities by using a diamond nanograting with a pitch of 400 nm and a depth of 3 μm. Exemplary patterning techniques are described in Bishop et al., "Deterministic nanopatterning of diamond using electron beams," ACS Nano 2018, 12, 3, 2873-2882, and Toros et al., "Reactive ion etching of single crystal diamond by inductively coupled plasma: State of the art and catalog of recipes," Diamond and Related Materials 108, 107839, 10.1016 / j.diamond.2020.107839. Such techniques can be used when targeting PDMR applications, although different specific geometries may be desirable to optimize electrode placement.

[0041] For example, standard photolithography techniques can be used with sub-micron resolution if coatings such as metallization are used to form the necessary electrical contacts. An exemplary electrode standard pattern is an interdigitated electrode, as described in Siyushev et al., "Photoelectrical imaging and coherent spin-state readout of single nitrogen-vacancy centers in diamond," Science 15 Feb 2019, 728-731.

[0042] The dimensions of each sensing area depend on the size of the device and the type of sensing required. Typically, these sensing areas have a maximum linear dimension (diameter in case of a circular sensing area) on the order of millimeters, but can also be 1000 μm or less, 100 μm or less, 50 μm or less, 10 μm or less, and 1 μm or less. Different surface patterning or metallization methods all allow even smaller minimum dimensions or around 1 μm. Considering the sample to be measured (e.g., liquid sample in a microfluidic channel), the sensing area can be as small as a few μm for nano-NMR applications and much larger areas (up to mm) for wide-field detection of biomarkers.

[0043] 4 is a flow diagram showing steps for forming a sensor device. The following numbering corresponds to that of FIG. S1. Provide a first sensing surface area on a diamond material. S2. Providing a second sensing surface area on the diamond material. The diamond material can be the same diamond material as that on which the first sensing surface area is provided. Both the first and second sensing surface areas are within interaction distance of their respective spin defects such that the spin defects can be used to sense properties of materials in contact with or adjacent to each of the first and second sensing surface areas. Exemplary spin defects include negatively charged nitrogen vacancy centers, silicon vacancy centers, tin vacancy centers, germanium vacancy centers, nickel-related defects, and chromium-related defects. The concentration of spin defects adjacent to the first sensing surface area can be different from the concentration of spin defects adjacent to the second sensing surface area. Additionally, a surface pattern can be applied to the surface of the diamond material on either the first or second sensing surface area, and a metallized coating can be applied to form electrical contacts. S3. Provide a magnetic excitation source configured to apply a bias magnetic field and provide a light source to induce a photoelectric effect in the spin defects. S4. Provide a current detector configured to detect charge carriers excited from one or more spin defects proximate to at least one of the sensing surface areas.

[0044] An exemplary method of manufacturing a diamond sensor comprising different sensing areas in proximity to different concentrations of spin defects can then be carried out using the process described in WO 2020 / 201211. During synthesis, the nitrogen doping level is controlled to produce layers of different nitrogen concentrations. The substrate is then removed and the remaining material is sliced ​​vertically. After irradiation and annealing, the plate is overgrown with a low impurity layer as described in WO 2001 / 096634. For example, diamond sensor device 1 has an underlayer of diamond with very low nitrogen impurities. A first sensing surface area 2 is present on a layer of diamond material with a nitrogen concentration of 50 ppb and a second sensing surface area 3 is present on a layer of diamond material with a nitrogen concentration of 5 ppm.

[0045] Such structures can be formed by growing two layers with different nitrogen concentrations and then overgrowing a low nitrogen layer on both nitrogen-containing layers. Alternatively, a low nitrogen layer of diamond can be provided and a mask applied before overgrowing the areas with high nitrogen concentration. Quite complex structures can be constructed in this manner.

[0046] Alternatively, low nitrogen diamond material can be provided as described in WO 2001 / 096634. By masking selected areas, ion implantation can be used to inject spin defects precursor defects to form spin defects such as NV centers, which can be treated, for example, by irradiation and annealing. Ion implantation is described in Wannemacher et al., "Generation and detection of fluorescent color centers in diamond with submicron resolution," App Phys Lett, 75(20), 3096-3098.

[0047] Figure 5 shows a sensor device in which the sensor 1 shown in Figure 1 is placed in proximity to a material 15 to be sensed. A magnetic bias field 16 is placed in proximity to the sensor 1 to generate excitation energy directed to one or more spin defects in the diamond material. A light source 17 is provided to excite electrons into the conduction band. A current detector 18 is configured to detect charge carriers excited from the one or more spin defects in proximity to at least one of the sensing surface areas. One or more photoelectric detectors may be provided. Importantly, the one or more photoelectric detectors are capable of individually interrogating spin defects in proximity to each of the first and second sensing areas.

[0048] To interrogate each sensing surface area individually using PDMR, electrodes must be placed in close proximity to the spin defects associated with each sensing surface area. E-beam lithography techniques allow electrodes to be deposited on a surface with high precision. This allows electrode arrays to be deposited such that a pair of electrodes can selectively address a single NV center. The first advantage of this technique is that it allows the rapid evaluation of the properties (orientation, stability) of each NV sensor as well as the rapid establishment of a map of preferred NV centers. The second advantage is that selected independent single NV centers can be manipulated simultaneously. The distance between single NV centers that can be individually addressed is limited by the resolution of photolithography techniques to fabricate electrodes better than the diffraction limit. This technique allows for improved applications using single NV center arrays and is particularly interesting for quantum information processing.

[0049] The electrodes do not need to be deposited on the diamond surface. PDMR can be optimized if the charge collection occurs not only at the electrodes placed on the surface of the diamond, but also when conductive regions are provided within the body of the diamond. In this way, the charge collection can be optimized to improve the collected signal and sensitivity, and more diamond can be utilized. Furthermore, the individual spin centers of the diamond can be interrogated. To function, the spin centers and the conductive region must be located within an interaction distance. In practice, this usually means that the spin centers and the conductive region are within a charge carrier drift length in order for the charge carriers from the spin centers to reach the conductive region and be detected. 5×10 4 V cm -1 For a typical electric field of 0.25 V, taking into account typical mobilities and recombination lifetimes, the theoretical drift length of charge carriers in diamond varies from over a meter for ultra-high quality diamond with nitrogen impurity concentrations in the ppb range to less than 20 μm for highly defective diamond.

[0050] It should be noted that the device shown in Figure 5 shows a single piece of diamond having two sensing surface areas, it is also possible to form a device where the first sensing surface area is located on a surface of a first diamond material and the second sensing surface area is located on a surface of a second diamond material.

[0051] 6, a flow diagram illustrating exemplary steps for using the sensor device described above is shown. The following numbering corresponds to the numbering in FIG. S5. Position a sensor device having at least a first and a second sensing area in proximity to the substance to be analyzed. As mentioned above, typically the first and second sensing areas are optimized to sense different properties. S6. Obtain a first measurement from a first at least one spin defect associated with the first sensing area. S7. Obtain a second measurement from a second at least one spin defect associated with the second sensing area, where the first and second measurements can be obtained simultaneously or sequentially depending on the capabilities and sensing requirements of the PDMR system.

[0052] The present invention as defined in the appended claims has been shown and described with reference to the above embodiments. However, those skilled in the art will appreciate that various changes in form and details may be made without departing from the scope of the invention as defined by the appended claims, and that although an exemplary compensation system has been described, other types of compensation systems that correct for temperature induced B field variations may also be used. [Explanation of symbols]

[0053] 1 Diamond sensor device 2. First sensing surface area 3 Secondary sensing surface area 4. Spin Defects 5. Spin Defects

Claims

1. A sensor device, comprising: a first sensing surface area; a second sensing surface area; Equipped with the first sensing surface area and the second sensing surface area are located on a diamond material; the first sensing surface area is within an interaction distance of a first at least one spin defect, the second sensing surface area is within an interaction distance of a second at least one spin defect, and the sensor device comprises: a magnetic excitation source configured to provide a bias magnetic field; a light source configured to excite spin defects to generate charge carriers in the conduction band; a current detector configured to detect charge carriers excited from one or more spin defects proximate at least one of the sensing surface areas; Further equipped with the first and second sensing surface areas being optimized for different sensing purposes; A sensor device, comprising: a concentration of spin defects adjacent to the first sensing surface area that is different from a concentration of spin defects adjacent to the second sensing surface area.

2. the first sensing surface area and the second sensing surface area are located on a surface of a single diamond material; The sensor device according to claim 1 .

3. the first sensing surface area is located on a surface of a first diamond material and the second sensing surface area is located on a surface of a second diamond material; The sensor device according to claim 1 .

4. any of the first and second at least one spin defect is selected from any of a negatively charged nitrogen vacancy center, a silicon vacancy center, a tin vacancy center, a germanium vacancy center, a nickel-related defect, and a chromium-related defect; The sensor device according to claim 1 .

5. either the first or second sensing surface area includes a surface pattern; The sensor device according to claim 1 .

6. either the first or second sensing surface area includes a metal coating that forms an electrical contact; The sensor device according to claim 1 .

7. The detection purpose is selected from the group consisting of nuclear magnetic resonance, magnetometry, and radio frequency spectroscopy; The sensor device according to claim 1 .

8. and further comprising a microwave source configured to control the spin defects. The sensor device according to claim 1 .

9. 1. A method of forming a sensor device, comprising: Providing a first sensing surface area; providing a second sensing surface area; the first and second sensing surface areas are located on a diamond material, the first sensing surface area is within an interaction distance of a first at least one spin defect and the second sensing surface area is within an interaction distance of a second at least one spin defect, the first and second sensing surface areas are optimized for different sensing purposes, and a concentration of spin defects adjacent to the first sensing surface area differs from a concentration of spin defects adjacent to the second sensing surface area, the method comprising: providing a magnetic excitation source configured to provide a bias magnetic field; providing a light source configured to excite charge carriers in a conduction band; providing a current detector configured to detect charge carriers excited from one or more spin defects proximate at least one of said sensing surface areas; The method according to claim 1, further comprising:

10. providing both said first sensing surface area and said second sensing surface area on a surface of a single diamond material.

10. The method of claim 9.

11. providing said first sensing surface area on a surface of a first diamond material and providing said second sensing surface area on a surface of a second diamond material; 10. The method of claim 9.

12. any of the first and second at least one spin defect is selected from any of a negatively charged nitrogen vacancy center, a silicon vacancy center, a tin vacancy center, a germanium vacancy center, a nickel-related defect, and a chromium-related defect; 10. The method of claim 9.

13. the first and second at least one spin defect are provided by any of doping the diamond during growth, ion implantation, annealing the diamond material, and irradiating the diamond material; 10. The method of claim 9.

14. providing one of a surface pattern and a metal coating on one of the first and second sensing surface areas.

10. The method of claim 9.

15. A method of using the sensor device according to claim 1, comprising: positioning the sensor device such that the first and second sensing surface areas are proximate to a substance to be analyzed; obtaining a first measurement from the first at least one spin defect; obtaining a second measurement from the second at least one spin defect; and The method according to claim 1, further comprising:

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