金刚石SiV色心的荧光辐射特性及其湮灭机制研究

Silicon vacancy (SiV) color center in diamond is believed to exhibit narrower zero phonon line(ZPL), stronger photoluminescence intensity and shorter excitation time than that in conventional quantum photoemitters such as semiconductor quantum dots, that is regarded as a new generation of distinguish single photon source. However, SiV color centers fabricated through CVD along with ion implantation suffer disadvantages such as small creation rate, low fluorescence intensity and even annihilation. In this program, SiV color center in diamond were prepared by microwave assisted CVD combined with ion implantation techniques. Vacancies and local stress were formed by carbon, hydrogen ions and electron beams’ irradiation and larger atomic germanium doping. Raman and photoluminescence spectra were carried out to investigate the evolution of the photoluminescence intensity with various vacancy density and local stress. Based on the experimental data and hypothesis, the mechanism of annihilation of photoluminescence of SiV color in diamond will be elaborated. The expected achievement of this program will bring solid background inspect of theoretical and technical support to prepare a single photon source. The highlights of this research program are as follows: (1) a single quantum photoemitter with high photoluminescence intensity, narrower zero phonon line and shorter excitation time is achieved by SiV color center in diamond; (2) the mechanism of fluorescence annihilation in SiV color center in diamond is explained through coupling interaction of phonon, electron and spin based on Jahn-Teller effect; (3) conversion of graphite induced by ion implantation to diamond by hydrogen etching and catalytic effects can be obtained to reduce the influence of graphitization of diamond on fluorescence.

与半导体量子点等常规量子光源相比，金刚石SiV色心具有更窄的零声子线、更强的荧光辐射和更短的受激时间，是新一代高品质单光子量子光源。然而，采用CVD法及离子注入法制备的金刚石SiV色心存在生成效率低、辐射强度弱、荧光骤降和湮灭等问题。本项目通过微波CVD法和离子注入协同实现硅掺杂，采用碳、氢和电子束辐照形成不同密度的空位分布，利用碳、硅的同族元素大原子锗掺杂形成局域应力，表征金刚石SiV色心荧光特性的演变规律，阐明金刚石SiV色心荧光辐射湮灭的机制，为高强度荧光辐射的金刚石SiV色心单光子源的制备提供理论和技术支持。本课题的主要创新点在于：(1) 以金刚石SiV色心为载体，实现高荧光辐射强度的单光子量子光源；(2) 基于Jahn-Teller效应，采用声子-电子-自旋耦合模型阐述SiV色心荧光辐射湮灭的机制；(3) 利用氢离子的刻蚀和催化非晶碳向金刚石相变，减少石墨化对荧光辐射的抑制。

本项目计划在高纯度金刚石外延生长及SiV 色心的多参数调控方法、载能离子束共注入生成SiV 色心及荧光特性优化、热处理工艺优化及SiV 色心性能演变、局域缺陷和石墨化协同作用下SiV 色心荧光辐射表征以及高辐射强度金刚石SiV 色心单光子源制备及优化技术等方面开展研究，重点解决原子级缺陷和应力作用下SiV 色心荧光辐射的高精度表征、声子-电子-自旋耦合作用抑制SiV 色心荧光辐射的机理等基础科学问题，获得了超高纯度单晶金刚石材料、实现了金刚石内NV和SiV色心的可控制备、通过异质界面调控色心的基本性能、发现了微纳结构单晶金刚石的超弹性应变工程导致的带隙动态演变特性等成果，在Science、Advanced Materials、Carbon、APL等学术期刊上发表论文10余篇，申请发明专利20余项，支撑科技部重点研发计划变革性技术专项、军科委基础加强项目的实施。.本项目针对金刚石SiV 色心荧光辐射湮灭问题，采用微波CVD 结合离子共注入法，研究硅掺杂、离子注入、退火等工艺过程中金刚石晶格畸变、局域应力和石墨化等因素的耦合规律，阐明上述因素影响金刚石SiV 色心荧光辐射性能的微观机制，提出增强金刚石SiV色心荧光辐射的实现方法，重点解决原子级缺陷和应力作用下SiV 色心荧光辐射的高精度表征、声子-电子-自旋耦合作用抑制荧光辐射机理等关键科学问题，为室温固态金刚石SiV 色心单光子量子光源的制备提供理论和技术支撑。.本项目执行期间，通过微波CVD法生长高纯度单晶金刚石、利用粒子注入等方式实现金刚石色心的有效可控注入、采用金刚石与金属的肖特基结结构获得了界面状态对金刚石色心特性的调控、利用铁掩膜可控实现金刚石的微细结构加工，同时探索发现微纳尺度下单晶金刚石的超弹性应变工程现象，为量子光源、下一代碳基芯片的研制提供基础。本项目完成了项目目标。