Crystalline BC₂N quantum dots

Ternary materials composed of boron, carbon, and nitrogen have drawn tremendous attention because of their suitable band gap, high carrier mobility, and high thermal conductivity. The properties can effectively compensate for the deficiencies of other typical carbon-based and boron-based materials, such as graphene, borophene, and hexagonal boron nitride. Although the theoretical progress has advanced the development of ternary materials, it is still a great challenge to synthesize the new nanostructures with good crystallinity and high yield at low dimensional scales. Herein, we report that BC₂N quantum dots (QDs) can be successfully prepared by in-situ two-step thermal decomposition of sodium cyanoborohydride in a hydrogen-rich environment. The results show that the as-prepared BC₂N QDs have good crystallinity and high yield. The BC₂N QDs have an average lateral size of 3.7 nm and an average thickness of 2.83 nm. The experimental results show that the QDs are semiconducting with an optical band gap of 2.15 eV. Furthermore, a fabricated BC₂N QDs-based nonvolatile memory shows a low SET operating voltage (0.74 V) and a high ON/OFF ratio (more than 1.74 × 10³) as well as good stability.