Abstract Point defects in semiconductors are emerging as an important contender platform for quantum technology (QT) applications, showing potential for quantum computing, communication, and sensing. Indeed, point defects have been employed as nuclear spins for nanoscale sensing and memory in quantum registers, localized electron spins for quantum bits, and emitters of single photons in quantum communication and cryptography. However, to utilize point defects in semiconductors as single‐photon sources for QT, control over the influence of the surrounding environment on the emission process must be first established. Recent works have revealed strong manipulation of emission energies and intensities via coupling of point defect wavefunctions to external factors such as electric fields, strain and photonic devices. This review presents the state‐of‐the‐art on manipulation, tuning, and control of single‐photon emission from point defects focusing on two leading semiconductor materials—diamond and silicon carbide.
Abstract Point defects in semiconductors are emerging as an important contender platform for quantum technology (QT) applications, showing potential for quantum computing, communication, and sensing. Indeed, point defects have been employed as nuclear spins for nanoscale sensing and memory in quantum registers, localized electron spins for quantum bits, and emitters of single photons in quantum communication and cryptography. However, to utilize point defects in semiconductors as single‐photon sources for QT, control over the influence of the surrounding environment on the emission process must be first established. Recent works have revealed strong manipulation of emission energies and intensities via coupling of point defect wavefunctions to external factors such as electric fields, strain and photonic devices. This review presents the state‐of‐the‐art on manipulation, tuning, and control of single‐photon emission from point defects focusing on two leading semiconductor materials—diamond and silicon carbide.
Abstract Color centers in diamond, silicon carbide, and related materials have recently emerged as one of the most promising platforms for quantum technology applications. These optically active point defects in the crystal lattice demonstrate outstanding optical and spin properties at room and even higher temperatures, which can hardly be achieved using other quantum systems. For a long time, the host material was considered only as a mechanical carrier of color centers, and the fact that it is a semiconductor and, therefore, can contain high densities of electrons and holes, was ignored. However, recent studies have demonstrated that color centers can exchange electrons and holes with the valence or conduction bands of the host material, which enables novel functionalities, ranging from ultrabright electrically driven single‐photon sources to protected quantum memories. This review summarizes recent advances in understanding this interaction.
Deep-level defects are usually considered undesirable in semiconductors as they typically interfere with the performance of present-day electronic and optoelectronic devices. However, the electronic spin states of certain atomic-scale defects have recently been shown to be promising quantum bits for quantum information processing as well as exquisite nanoscale sensors due to their local environmental sensitivity. In this review, we will discuss recent advances in quantum control protocols of several of these spin defects, the negatively charged nitrogen-vacancy (NV-) center in diamond and a variety of forms of the neutral divacancy (VV0) complex in silicon carbide (SiC). These defects exhibit a spin-triplet ground state that can be controlled through a variety of techniques, several of which allow for room temperature operation. Microwave control has enabled sophisticated decoupling schemes to extend coherence times as well as nanoscale sensing of temperature along with magnetic and electric fields. On the other hand, photonic control of these spin states has provided initial steps toward integration into quantum networks, including entanglement, quantum state teleportation, and all-optical control. Electrical and mechanical control also suggest pathways to develop quantum transducers and quantum hybrid systems. The versatility of the control mechanisms demonstrated should facilitate the development of quantum technologies based on these spin defects.
Quantum emitters serve as essential on-demand photonic resources, generating quantum states of light such as single photons and entangled photon pairs while serving as interfaces between light and matter. Buried in the solid state, quantum emitters enable a straightforward adoption of advanced nanofabrication techniques, facilitating precise engineering of their photonic environment for scalable quantum technologies. In this review, we introduce the fundamentals of quantum emitters and the key metrics characterising their performance. We highlight three material platforms: quantum dots, defect centres in diamond, and defect centres in silicon carbide. We summarise the recent developments of these platforms and discuss their advancements in quantum applications, including quantum communication, computation, and sensing. Finally, we provide a comparison across the three platforms, along with an outlook on future directions and potential challenges.
In the past decade, color centers in silicon carbide (SiC) have emerged as promising platforms for various quantum information technologies. There are three main types of color centers in SiC: silicon-vacancy centers, divacancy centers, and nitrogen-vacancy centers. Their spin states can be polarized by laser and controlled by microwave. These spin defects have been applied in quantum photonics, quantum information processing, quantum networks, and quantum sensing. In this review, we first provide a brief overview of the progress in single-color center fabrications for the three types of spin defects, which form the foundation of color center-based quantum technology. We then discuss the achievements in various quantum sensing, such as magnetic field, electric field, temperature, strain, and pressure. Finally, we summarize the current state of fabrications and quantum sensing of spin defects in SiC and provide an outlook for future developments.
Abstract Silicon carbide (SiC) is an excellent industrially compatible material, which has been widely used in high power electronic devices. Recently, spin defects in SiC have been found to be a high-quality spin-to-photon interface with long spin coherence time and high spin-selective optical transition. Spin states can be initialized and readout with extremely high fidelity. The infrared and even telecom fluorescence is suited for fiber communication with less scatting loss. The bandwidth of intrinsic zero-phonon-line emission can be manipulated by classical electrical devices. The achieved near lifetime-limited optical linewidths greatly increase the indistinguishability of photon emission and facilitate the connection with other narrowband absorption quantum systems, such as cold atoms, trapped ions, and rare-earth dopants in crystals. Moreover, spin defects coupled with photonic nanocavities have been demonstrated, which can greatly enhance the photon emission in the zero-phonon-line. The realization of controllable electron-nuclear spin entanglement further extends the memory-based quantum applications. In this perspective, we will briefly discuss the most recent development of spin defects in SiC. These results show that spin defects in SiC are desirable quantum platforms for quantum networking applications. We also discuss some of the current challenges and possible future development.
Quantum networks based on solid-state spin defects present a transformative approach to secure communication and distributed quantum computing, utilizing quantum entanglement and coherent spin–photon interfaces. Silicon carbide (SiC) stands out as a compelling material platform due to its unique combination of a wide bandgap, high optical nonlinearity, CMOS-compatible fabrication, and controllable spin-active defects. These intrinsic properties facilitate efficient photon emission, robust spin coherence at both room and cryogenic temperatures, and integration with photonic nanostructures. Recent advancements in defect engineering and micro-nanophotonics have unlocked the potential of SiC quantum nodes, which feature electron-nuclear spin systems for high-fidelity quantum operations and long-lived quantum memories. Key steps such as single-shot readout and spin-photon entanglement have been successfully demonstrated, bringing SiC closer to a real quantum network platform. This review offers a comprehensive overview of the advancements in SiC-based quantum networks, encompassing key aspects such as defect fabrication methodologies, optimization of spin-photon interfaces, and strategies for photonic integration. Additionally, it examines the existing challenges and outlines promising future directions in this rapidly evolving field.