EAGER: Manufacturing of Diamond Nanocrystals for Quantum Applications

这项探索性研究（EAGER）早期概念奖旨在研究金刚石晶体阵列纳米制造的基础科学和工程，用于许多新应用，如量子计算、磁场传感、自旋电子学、加密和纳米医学。含有氮空位（NV）缺陷中心的金刚石纳米晶体显示出可以由微波、光信号、电场和磁场控制的特性，从而使它们在无数量子应用中有用。作为量子器件的组件，每个纳米或微米尺寸的金刚石单晶最好只包含一种NV缺陷中心，并且当排列成孤立的金刚石单晶阵列时，可以实现最大的灵敏度和单个寻址性。该项目开发了制造含有NV缺陷中心的金刚石单晶阵列的方法，该缺陷中心优先沿单晶学方向取向。此外，该项目还为研究生和本科生提供教育和培训，以促进他们在学术界或工业界的劳动力发展和职业发展。这些研究成果被传播到科学界，预计将对几个国家计划产生重大影响，如先进制造、纳米技术、量子信息科学、光电子学、医学和国家安全。最先进的量子技术采用含有NV缺陷的金刚石薄膜或体晶体，这些薄膜或体晶体不适合广泛使用，因为NV缺陷是随机分布的，在许多新的量子应用中不能单独解决。该项目的目标是演示具有增强的NV缺陷中心优选方向的外延金刚石单晶阵列制造的概念验证。整个计划的科学依据基于三个变革性假设，其中包括：(1)偏置增强成核，用于在图案化单晶硅衬底上创建外延金刚石核阵列，随后是金刚石晶体的生长；(2)基于平面原子密度，衬底取向促进NV缺陷中心沿111晶体方向优先取向的作用；(3)在微波等离子体增强化学气相沉积（MPECVD）制造过程中应用电场和/或磁场，以额外优先对准NV缺陷中心。该项目促进了对氮原位掺杂、金刚石成核和生长机制、衬底取向以及施加在NV缺陷中心上的电场和/或磁场的作用的基本理解。金刚石纳米晶体的质量是通过定量表征自旋态可寻址性来确定的，该自旋态可寻址性基于纳米晶体暴露于光探测磁共振微波和激光泵浦后的光发射变化。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

This EArly-concept Grants for Exploratory Research (EAGER) award aims at studying the fundamental science and engineering for nanomanufacturing of diamond crystal arrays for use in many novel applications, such as, quantum computing, magnetic field sensing, spintronics, encryption, and nanomedicine. Diamond nanocrystals containing nitrogen-vacancy (NV) defect centers display properties that can be controlled by microwave, optical signal, electric and magnetic fields thereby making them useful for a myriad of quantum applications. To function as components of quantum devices, each nanometer or micrometer size diamond single crystal should preferably contain only one type of NV defect center and, when arranged into isolated diamond single crystal arrays, achieve the greatest sensitivity and individual addressability. This project develops approaches to manufacture diamond single crystal arrays containing NV defect centers that are preferentially oriented along a single crystallographic direction. In addition, the project provides education and training to graduate and undergraduate students towards workforce development and careers in academia or industry. The research findings are disseminated to the scientific community and expected to have significant impacts on several national initiatives such as advanced manufacturing, nanotechnology, quantum information sciences, optoelectronics, medicine, and national security.The state-of-the-art in quantum technology employs diamond thin films or bulk crystals containing NV defects that are unsuited for wide-spread use because the NV defects are randomly distributed and cannot be individually addressed for many of the novel quantum applications. The objective of the project is to demonstrate proof-of-concept for manufacturing of epitaxial diamond single crystal arrays with enhanced preferred orientation of the NV defect centers. The scientific justifications for the overall program are based on three transformative hypotheses that include (1) bias-enhanced nucleation for creating an array of epitaxial diamond nuclei on patterned single crystal silicon substrates followed by the growth of the diamond crystals; (2) role of substrate orientations promoting preferential orientation of the NV defect centers along 111 crystallographic direction based on planar atom density; and (3) application of electric and/or magnetic fields during manufacturing by Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) for additional preferential alignment of the NV defect centers. The project advances the fundamental understanding of the roles of in situ doping by nitrogen, diamond nucleation and growth mechanisms, substrate orientation, and applied electric and/or magnetic fields on the NV defect centers. The quality of the diamond nanocrystals is determined by quantitative characterization of spin state addressability based on changes in optical emission upon exposure of the nanocrystals to microwave and laser pumping using optically detected magnetic resonance.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.