Silicon carbide single-photon sources: challenges and prospects

The search for an ideal single-photon source (SPS) with superior emission properties is still at the core of many research efforts in optical quantum technologies and the criteria identifying a perfect SPS are now well outlined in various roadmaps established to develop future quantum communication networks. While many efforts have been placed into optimizing quantum dots in hybrid nanophotonic structures, these sources are limited by low-temperature operation and characterized by not yet facile and scalable engineering processes. Alternative material platforms have emerged to address room temperature operation and more achievable scalability and control. One of these platforms is silicon carbide (SiC). In this perspective, we first provide a very broad timelined introduction on last 30 years’ efforts developing SPSs, and then we provide a general outline of recent improvements in uncovering and evolving room-temperature SPSs in SiC viewed in a broader context. We will focus on some specific color centers or intra-bandgap defects and discuss challenges in their further expected development into scalable and robust integrated photonic platforms for nonlinear integrated photonics and spin–photon entanglement generation and distribution. A general comparison with other emerging platforms for SPS is also provided to identify comparative achievements, prospects, and challenges.