Millimeter-Sized Monoisotopic Cubic ¹⁰Boron Phosphide

Boron isotope-containing semiconductors with many novel physical properties have attracted extensive research interest in the areas such as device thermal management, optical components, and neutron detection. However, the existence of strong intrinsic covalent bonding leads to the high-temperature and high-pressure growth conditions of the single crystals of B-compound semiconductors, which has been a great bottleneck limiting their development. Here, high-quality monoisotopic cubic 10BP single crystals at a millimeter scale of approximately 1 mm were grown by a multistep ripening method based on the gas–liquid–solid principle for crystal growth. Structural and morphological analyses have shown that the 10BP single crystals prepared by this method possess a single cubic phase and high crystalline quality. The isotopic effect gives rise to the shift of characteristic peaks in the Raman spectrum. Besides, results obtained through reflection spectrum, photoluminescence (PL), and theoretical calculations demonstrate that 10BP is a semiconductor with an indirect band gap beyond 2 eV. All of these findings can prove that the multipart maturation method is a feasible way to synthesize high-quality 10BP single crystals, which provides a novel and competitive route for the study of isotopic c-BP and the growth of large-sized crystals.