Methods and systems for engineering c-band telecom-wavelength quantum defects

Abstract

A method and system for engineering C-Band telecom-wavelength quantum defects centers, such as carbon-boron vacancy (CB-VB) and silicon-boron vacancy (SiB-VB) complex centers, in hexagonal boron nitride (h-BN), the method including growing a h-BN thin epilayer, or a semi-bulk thick layer, using a semiconductor epitaxial growth processing tool, doping one or more of said h-BN thin epilayer, or said semi-bulk thick layer, with carbon or silicon impurities during the growing to create defect complexes comprising (CB-VB) and (SiB-VB), controlling a growth rate and V / III ratio during the growing, and producing h-BN wafers and thin epilayers with the (CB-VB) and (SiB-VB) quantum defect centers as single photon emitters in the conventional band of telecom wavelengths as well as qubits.

Description

PATENT COOPERATION TREATYTITLE: Methods and Systems for Engineering C-Band Telecom-Wavelength Quantum DefectsINVENTOR: Hongxing Jiang, Jing Li, Jingyu Lin, Musab Almohammad, Zaid AlemoushCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims the benefit of U.S. Provisional Application No. 63 / 585,111, titled “METHODS AND SYSTEMS FOR ENGINEERING C-BAND TELECOMWAVELENGTH QUANTUM DEFECTS” filed September 25, 2023, the content of which is incorporated herein by reference in its entirety for all purposes.TECHNICAL FIELD

[0002] The present disclosure relates to the field of quantum information science and engineering (QISE) with a focus on quantum defect centers, and their applications in quantum information technology. In particular, the present disclosure relates to engineering conventional band (C-band) telecom-wavelength quantum defects in hexagonal boron nitride (h-BN) for quantum information technology.STATEMENT OF FEDERALLY FUNDED RESEARCH

[0003] This invention was made with United States Government support under Grant ID No. DE- AR0001552, awarded by the Department of Energy. The United Sates Government has certain rights in this invention.BACKGROUND

[0004] A major problem facing the field of quantum information science and engineering (QISE) is the limited scalability and compatibility of current quantum hardware technologies. Quantum computers (QCs) based on various qubit systems have demonstrated exponential advantages overclassical computers, but they are often bulky, require expensive peripheral systems, and emit photons at wavelengths that result in significant losses when transmitted through fiber-optic cables.

[0005] Currently, leading qubit technologies, such as superconducting transmons, trapped ions, and quantum optics, face significant challenges in achieving scalability beyond a few hundred qubits. Moreover, the negatively charged nitrogen-vacancy (NV) centers in diamond, which have attracted attention, emit photons predominantly at a wavelength (637 nm) that does not align with the minimum loss spectrum of typical fiber-optic cables.

[0006] The pressing need arises from the limitations of existing quantum hardware, as they hinder the practical realization of large-scale quantum information processing systems. To fully harness the potential of QISE, there is a demand for quantum defect centers in materials that emit photons within telecom-wavelength ranges, minimizing transmission losses, and thereby facilitating the integration of quantum technologies into existing optical infrastructure.

[0007] Accordingly, there is a need for the development of technology capable of engineering quantum defect centers in semiconductors with emission wavelengths that align with the conventional band (C-band from 1530 to 1565 nm) of telecom -wavelength, where light loss is minimized in standard fused silica glass fibers. Additionally, there is a need to achieve precise and controllable generation of these quantum defect centers in semiconductor materials to enable their widespread utilization.

[0008] Therefore, the field of quantum information science and engineering (QISE) needs a solution that can provide engineering technology that can create quantum defects in semiconductors. Hexagonal boron nitride (h-BN) is an ultrawide bandgap semiconductor and is shown to be an excellent host for quantum defects with tailored emission wavelengths in theconventional optical communication band, addressing the limitations of existing quantum hardware and paving the way for efficient quantum information technology integration.SUMMARY OF THE DISCLOSURE

[0009] The present disclosure is directed to systems and methods for discovering carbon (C) and silicon (Si) related telecom -wavelength quantum defects in hexagonal boron nitride (h-BN) and more specifically for generating quantum defects formed by (CB-VB) and (SIB-VB) complex centers in h-BN for quantum information technology applications, where (CB-VB) complex center consists of a carbon impurity occupying boron site (CB) and a boron vacancy (VB), whereas (SIB-VB) complex center consists of a silicon impurity occupying boron site (Sis) and a boron vacancy (VB).

[0010] To address the need disclosed above, the present disclosure provides a quantum information science and engineering technology that tackles the problem of limited scalability and compatibility of current quantum hardware technologies by introducing a novel method to engineer (CB-VB) and (SIB-VB) complexes in hexagonal boron nitride (h-BN) with tailored emission wavelengths within the C-band of telecom -wavelength (1530 to 1565 nm). By doing so, in certain embodiments, the present disclosure significantly reduces the optical losses during photon transmission through fiber-optic cables, making it compatible with existing optical infrastructure and eliminating the need for costly peripheral systems.

[0011] Moreover, the technology of the present disclosure provides a precise and controllable means to generate quantum defect centers in h-BN, addressing the challenge of creating these centers in semiconductor materials in specific and controlled locations. As a result, in some embodiments, the systems and methods of the present disclosure offer a practical solution for theintegration of quantum information technology, overcoming the limitations of current quantum hardware and facilitating the realization of large-scale quantum information processing systems.

[0012] In general, in one embodiment, the disclosure features a method for generating (CB-VB) and (SIB-VB) quantum defect centers in hexagonal boron nitride (h-BN) including growing a h-BN thin epilayer and a semi-bulk thick layer using a semiconductor epitaxial growth processing tool, where the epitaxial growth processing tool comprises one or more of hydride vapor phase epitaxy (HVPE), metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), and molecular beam epitaxy (MBE). The method can also can include doping one or more of said h-BN thin epilayer and said semi-bulk thick layer with impurities during the growth to create boron vacancies and dopant-related defects. The method, in some embodiments, may additionally include, controlling a growth rate during the growth, wherein the controlling varies the concentration of boron vacancies. The method, in some embodiments, may additionally include, conducting thermal neutron irradiation to induce thermal neutron capture reactions. The method, in some embodiments, in response to conducting thermal neutron irradiation, can include creating (CB-VB) and (SIB-VB) quantum defect centers in the carbon or silicon doped h-BN layer. In some embodiments, the method can also include performing thermal annealing to facilitate the migration of boron vacancies under high temperature conditions. The method can also include producing h- BN wafers and thin epilayers with the (CB-VB) and (SIB-VB) quantum defect centers emitting single photons in the conventional C-band telecom wavelengths.

[0013] In general, in another embodiment, the disclosure features a system for generating (CB-VB) and (SIB-VB) quantum defect centers in h-BN, including a growth system in one or more of a hydride vapor phase epitaxy (HVPE), a metal organic chemical vapor deposition (MOCVD), a chemical vapor deposition (CVD), and a molecular beam epitaxy (MBE) apparatus; a substrateholder within the growth chamber, wherein the substrate holder is configured to support substrates selected from the group consisting of sapphire, silicon carbide (SiC), aluminum nitride (AIN), gallium nitride (GaN), silicon (Si), diamond, cubic boron nitride (c-BN), and hexagonal boron nitride (h-BN); a controlled source of impurities for doping the h-BN layers during growth, wherein the controlled source is operatively configured to create boron vacancies and dopant- related defects; and a wafer production module for producing h-BN wafers and thin epilayers with controlled (CB-VB) and (SIB-VB) quantum defect centers emitting single photons in the C-band of telecom wavelengths.BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Other advantages of the present disclosure will be apparent from the following detailed description of the disclosure in conjunction with embodiments as illustrated in the accompanying drawings, in which:

[0015] FIG. 1A depicts a schematic of a freestanding undoped h-BN wafer formation, in accordance with certain embodiments of the present disclosure.

[0016] FIG. IB depicts a schematic of a freestanding carbon doped h-BN (h-BN:C) wafer formation, in accordance with certain embodiments of the present disclosure.

[0017] FIG. 1C depicts carbon concentration probed by secondary ion mass spectrometry (SIMS) for a representative h-BN:C sample, in accordance with certain embodiments of the present disclosure.

[0018] FIG. 2 depicts room temperature photoluminescence (PL) spectra obtained under 260 nm laser excitation for a carbon doped h-BN (h-BN:C) sample and an undoped h-BN sample, in accordance with certain embodiments of the present disclosure.

[0019] FIG. 3 depicts photoluminescence (PL) emission intensity as a function of the x-ray diffraction (XRD) intensity of the diffraction peak corresponding to the h-BN (002) plane of h- BN:C samples measured in two-theta scans, in accordance with certain embodiments of the present disclosure.

[0020] FIG. 4 depicts room temperature photoluminescence (PL) spectra of a carbon doped h-BN (h-BN:C) sample obtained under 260 nm and 780 nm laser excitation, in accordance with certain embodiments of the present disclosure.

[0021] FIG. 5A depicts the energy level scheme of ground and first two excited states of Er ions in a silica glass, in accordance with certain embodiments of the present disclosure.

[0022] FIG. 5B depicts an absorption coefficient, oc, and emission coefficient, g*, spectra for a typical aluminum co-doped erbium doped fiber amplifier, in accordance with certain embodiments of the present disclosure.

[0023] FIG. 6A depicts a h-BN:C film directly deposited on a substrate, in accordance with certain embodiments of the present disclosure.

[0024] FIG. 6B depicts a h-BN:C film deposited on a substrate via an undoped h-BN epilayer template for enhanced crystalline quality, in accordance with certain embodiments of the present disclosure.

[0025] FIG. 6C depicts a freestanding h-BN:C wafer, in accordance with certain embodiments of the present disclosure.

[0026] FIG. 6D depicts a freestanding h-BN:C / h-BN wafer, in accordance with certain embodiments of the present disclosure.

[0027] FIG. 7A depicts a h-BN: Si film directly deposited on a substrate, in accordance with certain embodiments of the present disclosure.

[0028] FIG. 7B depicts a h-BN:Si film deposited on a substrate via an undoped h-BN epilayer template for enhanced crystalline quality, in accordance with certain embodiments of the present disclosure.

[0029] FIG. 7C depicts a freestanding h-BN: Si wafer, in accordance with certain embodiments of the present disclosure.

[0030] FIG. 7D depicts freestanding h-BN:Si / h-BN wafer, in accordance with certain embodiments of the present disclosure.

[0031] FIG. 8 depicts secondary ion mass spectrometry (SIMS) profiles of B and N contents in a h-BN wafer, in accordance with certain embodiments of the present disclosure.

[0032] FIGS. 9A-9D depict a processing flow to allow the generation of (CB-VB) and (SIB-VB) centers in precise locations in three-dimension, in accordance with certain embodiments of the present disclosure. FIG. 9A depicts MOCVD or HVPE growth, in accordance with certain embodiments of the present disclosure. FIG. 9B depicts formation of nanodisks via lithography / drying etching and VB via thermal neutron irradiation, in accordance with certain embodiments of the present disclosure. FIG. 9C depicts the device without re-growth of B-l 1 enriched h-nBN, in accordance with certain embodiments of the present disclosure. FIG. 9D depicts the device with re-growth of B-l l enriched h-nBN, in accordance with certain embodiments of the present disclosure.NOTATION AND NOMENCLATURE

[0033] Various terms are used to refer to particular system components. Different companies may refer to a component by different names - this document does not intend to distinguish between components that differ in name but not function. In the following discussion and in theclaims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . Also, the term “couple” or “couples” is intended to mean either an indirect or a direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection or through an indirect connection via other devices and connections.

[0034] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. Following long-standing patent law convention, the terms “a” and “an” mean “one or more” when used in this application, including the claims.

[0035] As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0036] The terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections; however, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer, or section from another region, layer, or section. Terms such as “first,” “second,” and other numerical terms, when used herein, do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the example embodiments. The phrase “at least one of,” when used with a list of items, means that different combinations of one or more of the listed itemsmay be used, and only one item in the list may be needed. As used herein, the term “and / or” when used in the context of a listing of entities, refers to the entities being present singly or in combination. Thus, for example, the phrase “A, B, C, and / or D” includes A, B, C, and D individually, but also includes any and all combinations and subcombinations of A, B, C, and D. Accordingly, as an example, “at least one of A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C. In another example, the phrase “one or more” when used with a list of items means there may be one item or any suitable number of items exceeding one.

[0037] Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” “top,” “bottom,” and the like, may be used herein. These spatially relative terms can be used for ease of description to describe one element’s or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms may also be intended to encompass different orientations of the device in use, or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

[0038] Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.DETAILED DESCRIPTION OF THE DISCLOSURE

[0039] The present disclosure is directed to systems and methods for discovering carbon (C) and silicon (Si) related telecom -wavelength quantum defects in hexagonal boron nitride (h-BN) and generating (CB-VB) and (SIB-VB complexes in h-BN for quantum information technology applications.

[0040] In some embodiments, undoped h-BN and carbon doped h-BN (h-BN:C) or silicon doped h-BN (h-BN: Si) thick films (semi -bulk wafers) were produced by hydride vapor phase epitaxy (HVPE) growth technique and investigated by photoluminescence emission spectroscopy. Boron chloride (BCI3) and ammonia (NH3) may be used as boron and nitrogen sources, respectively. The growth can be, in some embodiments, carried out using hydrogen as the carrier gas.

[0041] A low temperature h-BN buffer layer of tens of nanometers can be deposited on a c-plane sapphire substrate to serve as a nucleation layer. In some embodiments, the h-BN buffer layer of tens of nanometers can be deposited on a c-plane sapphire substrate at 800 °C.

[0042] In certain embodiments, the process may follow with the growth of an undoped h-BN epilayer deposited. The temperature, as a non-limiting example, may be at about 1500 °C. To obtain h-BN:C, in some embodiments, the growth of an undoped h-BN epilayer can be followed by the growth of a h-BN:C layer deposited at the same temperature, as shown schematically in FIGS. 1A and IB for h-BN and h-BN:C wafers, respectively. FIG. 1A depicts a schematic of a freestanding undoped h-BN wafer formation, in accordance with certain embodiments of the present disclosure. FIG. IB depicts a schematic of a freestanding carbon doped h-BN (h-BN:C) wafer formation, in accordance with certain embodiments of the present disclosure.

[0043] FIG. 1C depicts carbon concentration probed by secondary ion mass spectrometry (SIMS) for a representative h-BN:C sample, in accordance with certain embodiments of the present disclosure. As shown in FIG. 1C, which plots the carbon concentration in a representative h-BN:C sample probed by secondary ion mass spectrometry (SIMS) measurements, a carbon concentration of 7 x 1019cm’3in the interior of h-BN:C wafer was revealed.

[0044] For the IR photoluminescence measurements, the tripled and fundamental lasing wavelengths of a Ti-sapphire laser at Z,exc= 260 nm (Eexc= 4.77 eV) andexc= 780 nm (Eexe= 1 .59 eV) can be utilized as below bandgap excitation sources to provide excitations involving only impurity levels. The photoluminescence emission spectra can be collected using an InGaAs detector after being dispersed by a monochromator. In some embodiments, a long wavelengthpass filter can be placed in front of the slit of the monochromator to block the excitation laser line.

[0045] FIG. 2 depicts room temperature photoluminescence spectra obtained under 260 nm laser excitation for a carbon doped h-BN (h-BN:C) sample and an undoped h-BN sample, in accordance with certain embodiments of the present disclosure.

[0046] Room temperature PL spectra of carbon doped h-BN (h-BN:C) and undoped h-BN samples under 260 nm excitation measured in the spectral range from 0.7 to 0.9 eV, as is shown in FIG. 2. Further shown by FIG. 2, h-BN:C may exhibit a sharp emission line at 0.807 eV (or 1.54 pm) with a spectral line width as narrow as 5 meV at 300 K and a side band appearing at 0.799 eV of the same narrow linewidth is also highly visible, whereas the same emission peaks are completely absent in undoped h-BN. The results shown in FIG. 2 demonstrate an association between the telecom-wavelength emission line and the presence of carbon impurities introduced during the growth process.

[0047] As shown in FIG. 2, the side band at 0.799 eV observed in h-BN:C separates only by 8 meV from the main emission peak at 0.807 eV. The high phonon generation in h-BN of 8 meV in a h-BN encapsulated h-BN / MoS2 / h-BN system can be present due to an isolated phonon local mode.

[0048] In working embodiments of the present disclosure and as supported by the results depicted in FIG. 2, the calculated energy levels for CN acceptor (carbon occupying nitrogen site), CB donor (carbon occupying boron site), and Ci interstitial acceptor are EA = 3.19 eV, ED = 2.2 eV, and EA =2.4 eV, where EA and ED denote the energy levels of acceptor and donor, respectively, while a previous photocurrent excitation spectroscopy study performed in a h-BN:C thin epilayer suggested values of ED = 0.45 eV and EA =2.25 eV. Therefore, the main emission peak at 0.807 eV in FIG. 2 is not related to CN acceptor, CB donor (carbon occupying boron site), nor Ci interstitial acceptor.

[0049] In some embodiments, the formation of defect complexes can be enhanced by the presence of crystal imperfections including native defects such as nitrogen / boron vacancies as well as structural defects such as stack faults.

[0050] FIG. 3 depicts photoluminescence emission intensity as a function of the XRD intensity of the diffraction peak corresponding to the h-BN (002) plane of h-BN:C samples in two-theta scans, in accordance with certain embodiments of the present disclosure. Specifically, in accordance with certain embodiments, FIG. 3 shows PL emission intensity of the 0.807 eV emission line as a function of the XRD intensity of the (002) diffraction peak corresponding to the h-BN (002) plane of h-BN:C samples at 26.7° in two-theta (20) scans. The inset is the XRD 0-20 scan of a representative h-BN:C wafer.

[0051] As the XRD intensity of the (002) plane can reflect the relative crystalline quality among different samples, the PL emission intensity of this IR emission line as shown in FIG. 3 can be directly correlated with the crystalline quality, exhibiting an anti-correlation between the PL emission intensity at 0.807 eV and XRD intensity measured at 26.7°. Accordingly, FIG. 3 corroborates that the emission line at 0.807 involves a carbon complex, since crystalline quality is affected more by the presence of defect complexes than simple substitutional impurities.

[0052] FIG. 4 depicts room temperature photoluminescence spectra of a carbon doped h-BN (h- BN:C) sample obtained under 260 nm and 780 nm laser excitation, in accordance with certain embodiments of the present disclosure. To further show the nature of a carbon complex involved at the 0.807 eV emission line, PL emission spectra measurements were collected under excitation by two different below bandgap lasing wavelengths at 260 nm (4.77 eV) and 780 nm (1.59 eV), both of which have higher photon energies than 0.807 eV, the energy of the dominant emission line of interest. As shown in FIG. 4, when the excitation wavelength used is 260 nm, the emission line at 0.807 eV is observed. Conversely, when the excitation wavelength is 780 nm, the 0.807 eV emission line is absent.

[0053] The results shown in FIG. 4 together with the observation of such a narrow spectral line width of 0.807 eV emission line show that, in some embodiments, this emission line at the telecomwavelength is related to an internal transition within the defect complex, which requires excitation of electrons from a lower lying energy level to a higher lying energy level separating by an energy of more than 1.59 eV.

[0054] Complexes consisting of neutral boron vacancies (VB) and substitutional donors of carbon (CB) and silicon (Sis), denoted as (CB-VB) and (SIB-VB) can be difficult to form during the growth of cubic BN (c-BN). But (CB-VB) and (SIB-VB) would be excellent quantum defects if they can beformed in c-BN, as their related optical transitions occurring in the telecom wavelength O-band(1.260 to 1.360 pm). Moreover, (CB-VB) and (SIB-VB) possess a triplet ground state, like the NV center in diamond, which enables them to act as spin qubits.

[0055] With the experimental results represented in Figs 2-5, (CB-VB) and (SIB-VB), the present disclosure is in some embodiments based on the finding that impurity / defect complexes in h-BN have distinctive advantages compared to other candidates of quantum defects. The foremost advantage is the emission line of (CB-VB) and (SIB-VB) complexes in h-BN falls in the C-band of telecom wavelength which corresponds to photon wavelengths (approximately 1530 to 1560 nm) for which the attenuation in silica fibers is lowest.

[0056] Erbium doped fiber amplifiers (EDFAs) can possess the main optical emission spectral peak and hence highest gain at 1.53 pm as shown in FIGS. 5A and 5B. FIG. 5A depicts the energy level scheme of ground and first two excited states of Er ions in a silica glass, in accordance with certain embodiments of the present disclosure. In the case of the 4 In / 2 state, sp indicates the lifetime for nonradiative decay to the I13 / 2 first excited state and ssp indicates the spontaneous lifetime of the 4 I13 / 2 first excited state. FIG. 5B depicts an absorption coefficient, a, and emission coefficient, g*, spectra for a typical aluminum co-doped erbium doped fiber amplifier (EDFA), in accordance with certain embodiments of the present disclosure.

[0057] The emission peak of the (CB-VB) defect in h-BN at 0.807 eV (or 1.54 pm), as depicted in FIGS. 5A and 5B, coincides well with the wavelength of highest gain of EDFAs. As shown in FIGS. 2 and 4, the second feature is the zero-phonon line at 0.807 eV (1.54 pm) can be overwhelmingly dominant and include 60% of the emitted photons. Accordingly, in some embodiments, a large fraction of emitted photons is in the well-defined quantum state that can beused for entanglement, in comparison to that of 3% of NV in diamond and 22% of (CB-VB) in c-BN.

[0058] Hexagonal phase is the equilibrium phase of the BN system at ambient pressure, which can enable the production of h-BN epitaxial layer and device structures in wafer scale by standard semiconductor epitaxial growth processing tools such as metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), chemical vapor deposition (CVD), molecular beam epitaxy (MBE) or combinations thereof.

[0059] Generating (CB-VB) and (SIB-VB) complexes in h-BN can involve carbon doped h-BN (h- BN:C) and silicon doped h-BN (h-BN:Si) thin epilayers and semi-bulk thick layers with layered structures, as shown in FIGS. 6A-6D and 7A-7D.

[0060] FIG. 6 A depicts a h-BN:C fdm directly deposited on a substrate, in accordance with certain embodiments of the present disclosure. FIG. 6B depicts a h-BN:C fdm deposited on a substrate via an undoped h-BN epilayer template for enhanced crystalline quality, in accordance with certain embodiments of the present disclosure. FIG. 6C depicts a freestanding h-BN:C wafer, in accordance with certain embodiments of the present disclosure. FIG. 6D depicts a freestanding h- BN:C / h-BN wafer, in accordance with certain embodiments of the present disclosure.

[0061] FIG. 7A depicts a h-BN: Si fdm directly deposited on a substrate, in accordance with certain embodiments of the present disclosure. FIG. 7B depicts a h-BN: Si fdm deposited on a substrate via an undoped h-BN epilayer template for enhanced crystalline quality, in accordance with certain embodiments of the present disclosure. FIG. 7C depicts a freestanding h-BN: Si wafer, in accordance with certain embodiments of the present disclosure. FIG. 7D depicts freestanding h- BN:Si / h-BN wafer, in accordance with certain embodiments of the present disclosure.

[0062] In some embodiments, the h-BN:C or h-BN:Si film can be directly deposited on a substrate, via an undoped h-BN epilayer template for enhanced crystalline quality; and freestanding h- BN:C / h:BN and h-BN:C wafers or h-BN:Si / h:BN and h-BN:Si wafers formed by self-separation after growth due to the difference in the thermal expansion coefficient between h-BN and substrate and h-BN’s layered structure. Since hexagonal phase is the equilibrium phase of the BN system at ambient pressure, in some embodiments, thin film growth techniques including but not limited to metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), chemical vapor deposition (CVD), plasma enhanced CVD, sputtering, molecular beam epitaxy (MBE), can be employed to produce these structures.

[0063] To enhance the probability of incorporation of (CB-VB) and (SIB-VB) complexes, in some embodiments, the concentration of boron vacancies in carbon and silicon doped h-BN can be controlled by V / III ratio, meaning the flow rates of precursors of nitrogen and boron can be varied to make h-BN slightly off from a perfect stoichiometry.

[0064] In certain embodiments, the growth rate can also be varied to control the concentration of boron vacancies. In such an embodiment, the concentration of boron vacancies increases with an increase of the growth rate.

[0065] FIG. 8 depicts the profiles of B and N contents in an h-BN wafer probed by secondary ion mass spectrometry (SIMS), in accordance with certain embodiments of the present disclosure. Specifically, an example of an h-BN film produced by HVPE that that contains boron vacancies is shown in FIG. 8, which plots B and N contents in a h-BN wafer probed by secondary ion mass spectrometry. As shown in FIG. 8, by calculating the ratio of [B] / [N] by averaging data points in the wafer’s interior revealed that the boron concentration is slightly less than the N concentration with a ratio of boron to nitrogen, [B] / [N] of 49.8 / 50.2. Knowing that the atomic density of h-BNis 1.1 x 1023 / cm3, this small deficiency in B content (0.2%) could potentially render a concentration of VB and its complex on the order of ~1O20cm'3, confirming that there are boron vacancies in this h-BN wafer.

[0066] The growth of h-BN isotope superlattices with creation and control of quantum defects in the present disclosure considers the prior challenges associated with optically active quantum spin centers in semiconductors. Specifically, the present disclosure considers that prior methods and systems experienced a lack of ability to generate these centers and arrays in controllable and precise locations without causing damage to the host materials. For h-BN, in some embodiments, (CB-VB) and (SIB-VB) complexes can be generated during growth by doping with carbon or silicon impurities and at the same time creating boron vacancies by controlling the V / III ratio or growth rate. But prior methods and systems were unable to effectively and consistent control such growth effectively and consistently.

[0067] In certain embodiments, the present disclosure uses the features which are unique to h-BN: very high and low thermal neutron capture cross-sections of10B andnB isotopes while all other properties of h-10BN and h-uBN are identical in order to address such challenge. In some embodiments, structures including but not limited to h-11BN / h-10BN:C / h-11BN (or h-”BN / h-10BN:Si / h-nBN) with each alternating layer consisting of a few layers of B-10 enriched h-10BN doped with carbon (h-10BN:C) or silicon (h-10BN:Si) and undoped B-l 1 enriched h-nBN can be grown on a substrate and then produced by HVPE, MOCVD, MBE, etc.

[0068] The alternating layer structures, in some embodiments, may define quantum defect locations in the direction along the c-axis (only the h-10BN layers will contain CB or S1B and VB). Accordingly, in such embodiments, the formation of nanodisks having a diameter D can be realized by electron-beam lithography (EBL) or UV lithography or extreme UV (EUV)lithography in conjunction with inductively coupled plasma (ICP) etching to define positions of VB and hence (CB-VB) or (SIB-VB) in the c-plane with10B atoms in all other areas being removed. VB generation in the nanodisk regions will be realized by thermal neutron irradiation via nuclear reaction of thermal neutron capture by10B atoms in the imbedded h-10BN:C (or h-10BN:Si) layers inside the nanodisk region.

[0069] FIGS. 9A-9D depict this processing flow to allow the generation of (CB-VB) and (SiB-Vs) centers in precise locations in three-dimension, in accordance with certain embodiments of the present disclosure. FIG. 9A depicts MOCVD or HVPE growth, in accordance with certain embodiments of the present disclosure. FIG. 9B depicts formation of nanodisks and VB via thermal neutron irradiation, in accordance with certain embodiments of the present disclosure. FIG. 9C depicts the device without re-growth of h-nBN, in accordance with certain embodiments of the present disclosure. FIG. 9D depicts the device with re-growth of h-nBN, in accordance with certain embodiments of the present disclosure.

[0070] In some embodiments, multiple alternating layers of h-11BN / h-10BN:C / h-11BN (or h-11BN / h-10BN:Si / h-11BN) can be repeated to form isotope superlattices with nanodisks.

[0071] To avoid oxygen (O) or Si and C diffusion from substrate, in certain embodiments, the growth of the first h-uBN layer in direct contact with the substrate can be grown at a lower temperature.

[0072] In some embodiments, the total number of layers underneath h-nBN can be controlled to approximately 10 or less to reduce the interaction between the defect complex (in the h-10BN layer) and substrate. To minimize any impact of oxidization of the defect complex in h-10BN layers, in certain embodiments, the structure can be completed with h-nBN at the top to avoid the directexposure to the air of the h-10BN layers where quantum defects are located. In such an embodiment, the practice will make the quantum defect centers more stable.

[0073] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the described embodiments. However, it should be apparent to one skilled in the art that the specific details are not required in order to practice the described embodiments. Thus, the foregoing descriptions of specific embodiments are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the described embodiments to the precise forms disclosed. It should be apparent to one of the ordinary skills in the art that many modifications and variations are possible in view of the above teachings.

[0074] While embodiments of the disclosure have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the disclosure. The embodiments described and the examples provided herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the disclosure disclosed herein are possible and are within the scope of the disclosure. The scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.

[0075] Embodiments can include be a system, a method, and / or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present disclosure.

[0076] Those skilled in the art will appreciate that the steps described herein may be carried out in a variety of ways and that no particular ordering is required. It will be further understood from the foregoing description that modifications and changes may be made in various embodiments ofthe present disclosure without departing from its true spirit. The descriptions in this specification are for purposes of illustration only and are not to be construed in a limiting sense.

[0077] Consistent with the above disclosure, the examples of systems and methods enumerated in the following clauses are specifically contemplated and are intended as a non-limiting set of examples.

[0078] Clause 1. A method for generating (CB-VB) and (SIB-VB) quantum defect centers in hexagonal boron nitride (h-BN) including growing a h-BN thin epilayer(s) or multiple doped h- BN layers or a semi-bulk thick layer using a semiconductor epitaxial growth processing tool, wherein the epitaxial growth processing tool comprises one or more of hydride vapor phase epitaxy (HVPE), metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), sputtering, and molecular beam epitaxy (MBE); doping one or more of said h-BN thin epilayer and said multiple doped h-BN layers and said semi-bulk thick layer with impurities during the growing to create boron vacancies and dopant-related defects; controlling the growth rate and V / III ratio during the growing, wherein the growth rate and V / III ratio controlling varies the concentration of boron vacancies; creating (CB-VB) and (SIB-VB) quantum defect centers in the h- BN layer(s); and producing h-BN wafers and thin epilayers with the (CB-VB) and (SIB-VB) quantum defect centers emitting single photons in the conventional band of telecom wavelengths.

[0079] Clause 2. A method for generating (CB-VB) and (SIB-VB) quantum defect centers in hexagonal boron nitride (h-BN) including growing a h-BN thin epilay er(s) or multiple B-10 and B-l 1 isotope enriched alternating h-BN layers or a semi-bulk thick layer using a semiconductor epitaxial growth processing tool, wherein the epitaxial growth processing tool comprises one or more of hydride vapor phase epitaxy (HVPE), metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), sputtering and molecular beam epitaxy (MBE);doping one or more of said h-BN thin epilayer(s) and said multiple B-10 and B-l 1 isotope enriched alternating h-BN layers and said semi-bulk thick layer with impurities during the growing; conducting thermal neutron irradiation to induce thermal neutron capture reactions by B-10 element; responsive to conducting thermal neutron irradiation, creating (CB-VB) and (SIB-VB) quantum defect centers in the doped h-BN layer(s); performing thermal annealing to enhance the migration of boron vacancies under high temperature conditions; and producing h-BN wafers and thin epilayers with the (CB-VB) and (SIB-VB) quantum defect centers emitting single photons in the conventional band of telecom wavelengths.

[0080] Clause 3. The method of any foregoing clause, where the growth process is conducted on a substrate selected from the group consisting of sapphire, silicon carbide (SiC), aluminum nitride (AIN), gallium nitride (GaN), AlGaN alloys, silicon (Si), diamond, cubic boron nitride (c-BN), and hexagonal boron nitride (h-BN).

[0081] Clause 4. The method of any foregoing clause, where the thermal neutron irradiation is utilized to precisely control the location of (CB-VB) and (SIB-VB) quantum defect centers in the h- BN layer(s) in the c-direction.

[0082] Clause 5. The method of any foregoing clause further includes forming nanodisk arrays in the h-BN layer(s) using electron-beam lithography or UV lithography or extreme UV (EUV) lithography and dry etching.

[0083] Clause 6. The method of any foregoing clause, where the forming the nanodisk arrays defines positions of the (CB-VB) and the (SIB-VB) in the c-plane.

[0084] Clause 7. The method of any foregoing clause, where the growing further comprises one or more of metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy(HVPE), chemical vapor deposition (CVD), plasma-enhanced CVD, sputtering, and molecular beam epitaxy (MBE) techniques.

[0085] Clause 8. The method of any foregoing clause, where the (CB-VB) quantum defect centers in the h-BN emit single photons in the C-band of telecom wavelengths in the range of 1530 to 1565 nm, specifically at wavelength regions around 1.54 pm.

[0086] Clause 9. The method of any foregoing clause, where the (SIB-VB) quantum defect centers in h-BN emit single photons in the C-band of telecom wavelengths, specifically in the range of 1530 to 1565 nm.

[0087] Clause 10. The method of any foregoing clause, where the (CB-VB) and (Sis-Vs) quantum defect centers exhibit a large fraction of single photons in the zero-phonon line.

[0088] Clause 11. The method of any foregoing clause, where the impurities comprise carbon (C), silicon (Si) impurities, or a combination thereof.

[0089] Clause 12. The method of any foregoing clause further includes growing the h-BN layers in a superlattice structure, wherein the (CB-VB) and (SIB-VB) quantum defect centers are positioned at precise locations in the c-direction within the superlattice structure.

[0090] Clause 13. The method of any foregoing clause, where the generation of (CB-VB) and (SIB- VB) quantum defect centers is achieved by subjecting the doped h-BN layer to thermal neutron irradiation.

[0091] Clause 14. The method of any foregoing clause, where the generation of (CB-VB) and (SIB- VB) quantum defect centers is enhanced by performing thermal annealing at elevated temperatures, facilitating the migration of boron vacancies to form (CB-VB) complexes from individually separated CB and VB, as well as forming (SIB-VB) complexes from individually separated S1B andVB.

[0092] Clause 15. The method of any foregoing clause, where the (CB-VB) and (SIB-VB) quantum defect centers in h-BN serve as quantum defects, single photon sources, and spin qubits.

[0093] Clause 16. The method of any foregoing clause, where the h-BN thin epilayers and semibulk thick layers doped with carbon (h-BN:C) comprise layer structures, wherein the layer structures comprise h-BN:C films directly deposited on a substrate, h-BN:C films deposited on a substrate via an undoped h-BN epilayer template to enhance crystalline quality, and freestanding h-BN:C / h-BN wafers.

[0094] Clause 17. The method of any foregoing clause, where the h-BN thin epilayers and semibulk thick layers doped with carbon (h-BN:C) comprise (CB-VB) complex quantum defects and emit photons in the C-band telecom wavelengths.

[0095] Clause 18. The method of any foregoing clause, where the h-BN thin epilayers and semibulk thick layers doped with silicon (h-BN: Si) comprise (SiB-VB) complex quantum defects and emit single photons in the C-band telecom wavelengths.

[0096] Clause 19. The method of any foregoing clause further includes fabricating nanodisk arrays from h-BN / h-BN:C / h-BN superlattices, wherein the superlattices control the (CB-VB) and the (Sin- VB) quantum defects’ positions in the c-plane.

[0097] Clause 20. The method of any foregoing clause further includes fabricating nanodisk arrays from h-BN / h-BN:Si / h-BN superlattices, wherein the superlattices control the (CB-VB) and the (S1B- VB) quantum defects’ positions in the c-plane.

[0098] Clause 21. A system for generating (CB-VB) and (SIB-VB) quantum defect centers in hexagonal boron nitride (h-BN), including a growth system including one or more of a hydride vapor phase epitaxy (HVPE), a metal organic chemical vapor deposition (MOCVD), a chemical vapor deposition (CVD), and a molecular beam epitaxy (MBE) apparatus; a substrate holder withinthe growth chamber, wherein the substrate holder is configured to support substrates selected from the group consisting of sapphire, silicon carbide (SiC), aluminum nitride (AIN), gallium nitride (GaN), silicon (Si), diamond, cubic boron nitride (c-BN), and hexagonal boron nitride (h-BN); a controlled source of impurities for doping the h-BN layers during growth, wherein the controlled source is operatively configured to create boron vacancies and dopant-related defects; and a wafer production module for producing h-BN wafers and thin epilayers with controlled (CB-VB) and (SIB-VB) quantum defect centers emitting photons in the C-band of telecom wavelengths.

[0099] Clause 22. The system of any foregoing clause further includes a control system configured to control growth rate and V / III ratio during a growth process.

[0100] Clause 23. The system of any foregoing clause further includes a thermal neutron irradiation source configured to induce thermal neutron capture reactions and configured to create (CB-VB) and (SIB-VB) quantum defect centers in the doped h-BN layer(s).

[0101] Clause 24. The system of any foregoing clause, where the thermal neutron irradiation source is configured to precisely control the location of (CB-VB) and (SIB-VB) quantum defect centers in the h-BN layer(s) in the c-direction.

[0102] Clause 25. The system of any foregoing clause further including a thermal annealing system, wherein the thermal annealing system is configured to enhance the migration of boron vacancies under high-temperature conditions leading to the formation of (CB-VB) and (SIB-VB) quantum defect centers from individually separated CB and VB or Sis and VB.

[0103] Clause 26. The system of any foregoing clause further including an electron-beam lithography (EBL) or UV or extreme UV (EUV) lithography and inductively coupled plasma (ICP) etching system for forming nanodisk arrays in the h-BN layer to define positions of VB and hence (CB-VB) or (SIB-VB) in the c-plane.

[0104] Clause 27. The system of any foregoing clause, where the growth system is configured to employ one or more of metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), chemical vapor deposition (CVD), plasma-enhanced CVD, sputtering, or molecular beam epitaxy (MBE) techniques to produce h-BN wafers or thin epilayers with controlled (CB-VB) and (SIB-VB) quantum defect centers.

[0105] Clause 28. The system of any foregoing clause, where the (CB-VB) quantum defect centers in h-BN emit single photons in the C-band of telecom wavelengths in the range of 1530 to 1565 nm, specifically at approximately 1.54 pm.

[0106] Clause 29. The system of any foregoing clause, where the (SIB-VB) quantum defect centers in h-BN emit single photons in the C-band of telecom wavelengths, specifically in the range of 1530 to 1565 nm.

[0107] Clause 30. The system of any foregoing clause, where the impurities comprise carbon (C), silicon (Si) impurities, or a combination thereof.REFERENCES

[0108] A. Gali, Nanophotonics 8, 1907 (2019).

[0109] A. Gottscholl, M. Diez, V. Soltamov, C. Kasper, A. Sperlich, M. Kianinia, C. Bradac, I. Aharonovich, V. Dyakonov, “Room temperature coherent control of spin defects in hexagonal boron nitride,” Sci. Adv. 7: eabf3630 (2021).

[0110] A. Gottscholl, M. Kianinia, V. Soltamov, S. Orlinskii, G. Mamin, C. Bradac, C. Kasper, K. Krambrock, A. Sperlich, M. Toth, I. Aharonovich, and V. Dyakonov, “Initialization and readout of intrinsic spin defects in a van der Waals crystal at room temperature,” Nature Materials, 19, 540 (2020).

[0111] A. Maity, S. J. Grenadier, J. Li, J. Y. Lin, and H. X. Jiang, Appl. Phys. Lett. 116, 142102(2020).

[0112] A. Maity, T. C. Doan, J. Li, J. Y. Lin, and H. X. Jiang, Appl. Phys. Lett. 109, 072101 (2016).

[0113] A. Tingsuwatit, A. Maity, S. J. Grenadier, J. Li, J. Y. Lin, and H. X. Jiang, Appl. Phys. Lett. 120, 232103 (2022).

[0114] F Arute, et al., “Quantum supremacy using a programmable superconducting processor,” Nature 574, 505 (2019).

[0115] G. F. Knoll, Radiation detection and measurement, 4th edition, John Wiley & Sons, (2010).

[0116] G. P. Agrawal, Fiber-Optic Communication Systems, 4th ed., Wiley Series in Microwave and Optical Engineering No. 222 (Wiley, New York, 2010).

[0117] H.-S. Zhong, et al., “Quantum computational advantage using photons,” Science 370, 1460-1463 (2020).

[0118] J. LJ. Wang, M. A. Yamoah, Q. Li, A. H. Karamlou, T. Dinh, B. Kannan, J. Braumuller, D. Kim, A. J. Melville, S. E. Muschinske, B. M. Niedzielski, K. Semiak, Y. Sung, R. Winik, J. L. Yoder, M. E. Schwartz, K. Watanabe, T. Taniguchi, T. P. Orlando, S. Gustavsson, P. Jarillo- Herrero and W. D. Oliver, “Hexagonal boron nitride as a low-loss dielectric for superconducting quantum circuits and qubits,” Nature Materials 21, 398 (2022).

[0119] J. Li, X. K. Cao, T. B. Hoffman, J. H. Edgar, J. Y. Lin, and H. X. Jiang, Appl. Phys. Lett. 108, 122101 (2016).

[0120] J.M. Chow, “Quantum Intranet,” IET Quantum Communications 2, 26-27 (2021).

[0121] K. Watanabe, T. Taniguchi, and H. Kanda, Nat. Photonics 3, 591 (2009).

[0122] L. Weston, D. Wickramaratne, M. Mackoit, A. Alkauskas, and C. G. Van de Walle, Phys.Rev. B 97, 214104 (2018).

[0123] M. E. Turiansky and C. G. Van de Walle, Physical Review B 108, L041102 (2023).

[0124] M. Kianinia, S. White, J. E. Froch, C. Bradac, and I. Aharonovich, “Generation of spin defects in hexagonal boron nitride,” ACS Photonics 7, 2147 (2020).

[0125] M. R. Uddin, J. Li, J. Y. Lin, and H. X. Jiang, Appl. Phys. Lett. 110, 182107 (2017).

[0126] N. Mendelson, et al, Nature Materials 20, 321 (2021).

[0127] N.P. De Leon, et al., “Materials challenges and opportunities for quantum computing hardware,” Science 372, eabb2823 (2021).O. Osberghaus, Zeitschrift fuer Physik 128 366 (1950).

[0128] R. Bourrellier, S. Meuret, A. Tararan, O. Stephan, M. Kodak, L. H. G. Tizei, and A.Zobelli, Nano Lett. 16, 4317 (2016).

[0129] S Fiore, C. Klinkert, F. Ducry, J. Backman, and M. Luisier, Materials (Basel) 15, 1062 (2022).

[0130] S Fiore, C. Klinkert, F. Ducry, J. Backman, and M. Luisier, Materials (Basel) 15, 1062 (2022).

[0131] S. Majety, J. Li, X. K. Cao, R. Dahal, B. N. Pantha, J. Y. Lin, and H. X. Jiang, Appl. Phys.Lett. 100, 061121 (2012).

[0132] T. Q. P. Vuong, G. Cassabois, P. Valvin, A. Ouerghi, Y. Chassagneux, C. Voisin, and B. Gil, Phys. Rev. Lett. 117, 097402 (2016).

[0133] T. Tran, C. Elbadawi, D. Totonjian, C. J. Lobo, G. Grosso, H. Moon, D. R. Englund, M. J. Ford, I. Aharonovich, and M. Toth, ACS Nano 10, 7331 (2016).

[0134] T. Tran, K. Bray, M. J. Ford, M. Toth, and I. Aharonovich, Nat. Nanotechnol. 11, 37(2016).

[0135] United States Patent No. 10,714,651, entitled “Solid-state neutron detectors.”

[0136] United States Patent No. 11,195,968 B2, entitled “Solid-state neutron detectors.”

[0137] United States Patent No. 9,093,581, entitled “Structures and devices based on boron nitride and boron nitride-III-nitride heterostructures.”

[0138] V. Ivady, G. Barcza, G. Thiering, S. Li, H. Hamdi, J. Chou, 0. Legeza and A. Gali, “Ab initio theory of the negatively charged boron vacancy qubit in hexagonal boron nitride,” npj Computational Material 6, 41 (2020).

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A method for generating (CB-VB) and (SIB-VB) quantum defect centers in hexagonal boron nitride (h-BN) comprising:(a) growing a h-BN thin epilayer or a semi-bulk thick layer, growing a carbon doped h-BN thin epilayer or a semi-bulk thick layer, and growing a silicon doped h-BN thin epilayer or a semi-bulk thick layer, using a semiconductor epitaxial growth processing tool, wherein the epitaxial growth processing tool comprises one or more of hydride vapor phase epitaxy (HVPE), metal organic chemical vapor deposition (MOCVD), chemical vapor deposition (CVD), plasma-enhanced CVD, sputtering and molecular beam epitaxy (MBE), wherein the growing allows for:(i) creating (CB-VB) and (SIB-VB) quantum defect centers in the doped h-BN layer,(ii) creating (CB-VB) and (Sin-Vn) quantum defect centers in the doped h-BN layer as single photon emitters in the conventional band of telecom wavelengths and as qubits;(b) doping one or more of said h-BN thin epilayer or said semi-bulk thick layer with impurities during the growing to create boron vacancies and dopant-related defects, wherein the doping results in:(i) creating (CB-VB) and (SIB-VB) quantum defect centers in the doped h-BN layer, and(ii) creating (CB-VB) and (SIB-VB) quantum defect centers in the doped h-BN layer as single photon emitters in the conventional band of telecom wavelengths and as qubits;(c) controlling a growth rate and V / III ratio during the growing, wherein the controlling varies the concentration of boron vacancies and henceforth the concentrations of (CB-VB) and (SIB-VB) quantum defect centers in the doped h-BN layer, creating (CB-VB) and (SIB-VB) quantum defect centers in the doped h-BN layer(s) as single photon emitters in the conventional band of telecom wavelengths and as qubits;(d) growing one or more of said h-BN thin epilayer or said semi-bulk thick layer with impurities and enriched with B-10 or B-l 1 isotope during the growing;(e) conducting thermal neutron irradiation to induce thermal neutron capture reactions in B-10 enriched h-BN layer(s);(f) responsive to conducting thermal neutron irradiation, creating (CB-VB) and (Sis- VB) quantum defect centers in the doped h-BN layer(s);(g) performing thermal annealing to facilitate the migration of boron vacancies under high temperature conditions; and(h) producing h-BN wafers and thin epilayers with the (CB-VB) and (SIB-VB) quantum defect centers emitting single photons in the conventional band of telecom wavelengths.

2. The method of Claim 1, wherein the growth process is conducted on a substrate selected from the group consisting of sapphire, silicon carbide (SiC), aluminum nitride (AIN), galliumnitride (GaN), silicon (Si), diamond, cubic boron nitride (c-BN), and hexagonal boron nitride (h- BN).

3. The method of Claim 1, wherein the thermal neutron irradiation is utilized to precisely control the location of (CB-VB) and (SIB-VB) quantum defect centers in the h-BN layer in the c- direction.

4. The method of Claim 1 further comprising forming nanodisk arrays in the h-BN layer using electron-beam lithography, UV lithography or extreme UV lithography and dry etching.

5. The method of Claim 4, wherein the forming the nanodisk arrays defines positions of the (CB-VB) and the (SIB-VB) quantum defect centers in the c-plane.

6. The method of Claim 1, wherein the growing further comprises one or more of metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), chemical vapor deposition (CVD), plasma-enhanced CVD, sputtering, and molecular beam epitaxy (MBE) techniques.

7. The method of Claim 1, wherein the (CB-VB) quantum defect centers in the h-BN emit single photons in the C-band of telecom wavelengths in the range of 1530 to 1565 nm, specifically at approximately 1.54 pm.

8. The method of Claim 1, wherein the (SIB-VB) and (CB-VB) quantum defect centers in h-BN emit single photons in the C-band of telecom wavelengths in the range of 1530 to 1565 nm.

9. The method of Claim 1, wherein the (C -VB) and (SIB-VB) quantum defect centers exhibit a large fraction of single photons in the zero-phonon line.

10. The method of Claim 1, wherein the impurities comprise carbon (C), silicon (Si) impurities, or a combination thereof.

11. The method of Claim 1, further comprising growing the h-BN layer in a superlattice structure comprising alternating B-10 and B-l l isotope enriched layers, or h-11BN / h-10BN:C / h-nBN superlattices, or h-11BN / h-10BN:Si / h-11BN superlattices, wherein the (CB-VB) and (Sis-Vs) quantum defect centers are positioned at precise locations in the c-direction within the superlattice structure.

12. The method of Claim 11, wherein the generation of (CB-VB) and (SIB-VB) quantum defect centers are achieved by thermal neutron absorption by B-10 elements by subjecting the doped h- BN layer to thermal neutron irradiation.

13. The method of Claim 11, wherein the generation of (CB-VB) and (SIB-VB) quantum defect centers is enhanced by performing thermal annealing at elevated temperatures, facilitating the migration of boron vacancies to form (CB-VB) complexes from individually separated CB and VB, as well as forming (SIB-VB) complexes from individually separated Sis and VB.

14. The method of Claim 1, wherein the (SIB-VB) quantum defect centers in h-BN serve as quantum defects, single photon sources, and spin qubits.

15. The method of Claim 1, wherein the h-BN thin epilayers or semi-bulk thick layers doped with carbon (h-BN:C) comprise layer structures, wherein the layer structures comprise h-BN:C films directly deposited on a substrate, h-BN:C films deposited on a substrate via an undoped h- BN epilayer template to enhance crystalline quality, and freestanding h-BN:C / h-BN wafers.

16. The method of claim 1, wherein the h-BN thin epilayers or semi -bulk thick layers doped with carbon (h-BN:C) comprise (CB-VB) complex quantum defects and emit single photons in the C-band telecom wavelengths.

17. The method of claim 1, wherein the h-BN thin epilayers or semi-bulk thick layers doped with silicon (h-BN: Si) comprise (SIB-VB) complex quantum defects and emit single photons in the C-band telecom wavelengths.

18. The method of claim 1, further comprising fabricating nanodisk arrays from h-nBN / h-10BN:C / h-nBN superlattices, wherein the superlattices define the (CB-VB) and the (SiB-VB) quantum defects’ positions in the c-direction and nanodisks define the (CB-VB) quantum defects’ positions in the c- plane.

19. The method of claim 1, further comprising fabricating nanodisk arrays from h-nBN / h-10BN:Si / h-nBN superlattices, wherein the superlattices define the (SIB-VB) quantum defects’ positions in the c-direction and nanodisks define the (SIB-VB) quantum defects’ positions in the c- plane.

20. A system for generating (CB-VB) and (SIB-VB) quantum defect centers in hexagonal boron nitride (h-BN), comprising:(a) a growth system comprising one or more of a hydride vapor phase epitaxy (HVPE), a metal organic chemical vapor deposition (MOCVD), a chemical vapor deposition (CVD), plasma-enhanced CVD, sputtering and a molecular beam epitaxy (MBE) apparatus;(b) a substrate holder within the growth chamber, wherein the substrate holder is configured to support substrates selected from the group consisting of sapphire, silicon carbide (SiC), aluminum nitride (AIN), gallium nitride (GaN), silicon (Si), diamond, cubic boron nitride (c-BN), and hexagonal boron nitride (h-BN);(c) a controlled source of impurities for doping the h-BN layers during growth, wherein the controlled source is operatively configured to create boron vacancies and dopant-related defects; and(d) a wafer production module for producing h-BN wafers and thin epilayers with controlled (CB-VB) and (SIB-VB) quantum defect centers emitting single photons in the C-band of telecom wavelengths.

21. The system of Claim 20 further comprising a control system configured to control growth rate and V / III ratio during a growth process.

22. The system of Claim 20 further comprising a thermal neutron irradiation source configured to induce thermal neutron capture reactions and configured to create (CB-VB) and (SIB-VB) quantum defect centers in the doped h-BN layer.

23. The system of Claim 22, wherein the thermal neutron irradiation source is configured to precisely control the location of (CB-VB) and (SIB-VB) quantum defect centers in the h-BN doped layer in the c-direction.

24. The system of Claim 20 further comprising a thermal annealing system, wherein the thermal annealing system is configured to facilitate the migration of boron vacancies under high- temperature conditions leading to the enhanced formation of (CB-VB) and (SIB-VB) quantum defect centers from individually separated CB and VB or S1B and VB.

25. The system of Claim 20 further comprising an electron-beam lithography (EBL), or UV lithography or extreme UV (EUV) lithography and dry etching such as inductively coupled plasma (ICP) etching system for forming nanodisk arrays in the h-BN layer to define positions of VB and hence (CB-VB) or (SIB-VB) in the c-plane.

26. The system of Claim 20, wherein the growth chamber is configured to employ one or more of metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE),chemical vapor deposition (CVD), plasma-enhanced CVD, sputtering, or molecular beam epitaxy (MBE) techniques to produce h-BN wafers or thin epilayers with controlled (CB-VB) and (CB-VB) or (SIB-VB) quantum defect centers.

27. The system of Claim 20, wherein the (CB-VB) quantum defect centers in h-BN as single photon emitters in the C-band of telecom wavelengths in the range of 1530 to 1565 nm, at approximately 1.54 pm.

28. The system of Claim 20, wherein the (SIB-VB) quantum defect centers in h-BN as single photon emitters in the C-band of telecom wavelengths, specifically in the range of 1530 to 1565 nm.

29. The system of Claim 20, wherein the impurities comprise carbon (C) impurities, silicon (Si) impurities, oxygen (O) impurities, or a combination thereof.

Images