Bottom-Up Fabrication of Single Photon Emitters in Hexagonal Boron Nitride

University of Technology Sydney. Faculty of Science.Emerging quantum technologies are currently limited by the development of robust hardware components to create, distribute, and readout quantum information. Single photon emitters are among the most fundamental components for most quantum information technologies. Among the most promising single photon sources are atom-like systems such as defects in solid-state materials, which can produce on-demand streams of single photons, are suitable for on-chip integration, and offer efficient spin-photon interfaces. As a result, materials such as diamond and silicon carbide have been intensely studied due to their bright and photostable emission, however, efficient integration methods remain a critical challenge. An intriguing alternative is the use of atomically thin materials which lack dangling bonds allowing for facile integration with nanophotonic components, display extremely efficient light-matter interactions, and be utilized to produce designer quantum states such as by stacking into van der Waals heterostructures. Here I study the 2D material hexagonal boron nitride (hBN) which can host ultra-bright single photon emission arising from point defects in the lattice. In this thesis I study the bottom-up fabrication of single photon emitters in hBN in great detail, demonstrating the incorporation of bright and optically stable emitters in large scale films comprised of only a few atomic layers. It is demonstrated that during growth we can reduce the inhomogeneous distribution of emission energies by over an order of magnitude and simultaneously control the density of incorporated single photon emitters. The smooth few layer nature of the films enables facile integration with nanophotonic components and with van der Waals heterostructures. I perform emission tuning studies on hBN thin films utilizing both Stark and strain methods, demonstrating record shift magnitudes for a 2D quantum light source, and revealing critical information on the level structure of the emissive defect. Finally, I study the structural nature of the defect finding a carbon based center is likely, a central question which has been debated since their initial discovery in 2015 and demonstrate optically detected magnetic resonance from these defects at room temperature for the first time