High yield growth of centimeter-sized black phosphorus single crystal thin flakes through bidirectional vapor transport

Black phosphorus (BP) has been regarded as a promising two-dimensional semiconductor due to its excellent properties including high carrier mobility and widely tunable direct bandgap. Despite extensive interest as well as research progress, the preparation of large-size and high-quality BP single crystal in high throughput still remains challenging. Here, a facile growth of centimeter-sized BP single crystal flakes with dozens of throughput per batch is achieved by using bidirectional vapor transport (BVT) method. High crystal quality is confirmed by structural and spectrum characterizations, with an X-ray diffraction rocking curve peak half-height width of only 0.02°. The as-grown BP single crystal flake with smooth cleavage plane can be easily exfoliated into large scale nanosheets. Field-effect transistors fabricated based on the BP by such approach show excellent performance including reliable carrier mobility up to 1150 cm² V⁻¹ s⁻¹ and on/off current ratio of ~10⁶ at 15 K. This approach is also applicable to various doped-BP, such as As-BP, Se-BP, Te-BP, etc. The ability to grow centimeter-sized BP single crystal flakes in high yield will accelerate the research and applications of BP-based electronics and optoelectronics.