Institute of Nano Science and Key Laboratory of Intelligent Nano Materials and Devices of Ministry of Education, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
J Am Chem Soc. 2011 Sep 21;133(37):14831-8. doi: 10.1021/ja206703x. Epub 2011 Aug 29.
Cubic boron nitride (c-BN) possesses a number of extreme properties rivaling or surpassing those of diamond. Especially, owing to the high chemical stability, c-BN is desired for fabricating electronic devices that can stand up to harsh environments. However, realization of c-BN-based functional devices is still a challenging task due largely to the subtlety in the preparation of high-quality c-BN films with uniform thickness and controllable properties. Here, we present a simple synthetic strategy by surface fluorination of few-layered hexagonal boron nitride (h-BN) sheets to produce thermodynamically favorable F-terminated c-BN nanofilms with an embedded N-N bond layer and strong inbuilt electric polarization. Due to these specific features, the fluorinated c-BN nanofilms have controllable band gap by thickness or inbuilt and applied electric fields. Especially, the produced nanofilms can be tuned into substantial ferromagnetism through electron doping within a reasonable level. The electron-doping-induced deformation ratio of the c-BN nanofilms is found to be 1 order of magnitude higher than those of carbon nanotubes and graphene. At sufficient high doping levels, the nanofilm can be cleaved peculiarly along the N-N bond layer into diamond-like BN films. As the proposed synthesis strategy of the fluorinated c-BN nanofilms is well within the reach of current technologies, our results represent an extremely cost-effective approach for producing high-quality c-BN nanofilms with tunable electronic, magnetic, and electromechanical properties for versatile applications.
立方氮化硼（c-BN）具有许多与金刚石相媲美的极端特性。特别是由于其化学稳定性高，c-BN 被用于制造能够承受恶劣环境的电子设备。然而，由于高质量、厚度均匀且性能可控的 c-BN 薄膜的制备具有挑战性，因此基于 c-BN 的功能器件的实现仍然是一个具有挑战性的任务。在这里，我们提出了一种通过少层六方氮化硼（h-BN）片表面氟化来制备热力学有利的 F 端 c-BN 纳米薄膜的简单合成策略，该纳米薄膜具有嵌入式 N-N 键层和强内置电极化。由于这些特定的特征，氟化 c-BN 纳米薄膜的带隙可以通过厚度或内置和外加电场来控制。特别是，通过在合理的范围内进行电子掺杂，可以将所制备的纳米薄膜调制成可观的铁磁性。所制备的纳米薄膜的 c-BN 电子掺杂诱导的变形比在碳纳米管和石墨烯高一个数量级。在足够高的掺杂水平下，纳米薄膜可以沿着 N-N 键层特别地劈开成类金刚石 BN 薄膜。由于氟化 c-BN 纳米薄膜的合成策略在当前技术范围内是可行的，因此我们的结果代表了一种非常具有成本效益的方法，可以生产具有可调电子、磁性和机电性能的高质量 c-BN 纳米薄膜，以实现各种应用。
