Department of Electrical Engineering, Yale University, New Haven, CT, 06511, USA.
Geophysical Laboratories, Carnegie Institution of Washington, Washington, DC, 20015, USA.
Adv Mater. 2018 Feb;30(6). doi: 10.1002/adma.201703748. Epub 2018 Jan 3.
Black phosphorus (BP) has recently attracted significant attention due to its exceptional physical properties. Currently, high-quality few-layer and thin-film BP are produced primarily by mechanical exfoliation, limiting their potential in future applications. Here, the synthesis of highly crystalline thin-film BP on 5 mm sapphire substrates by conversion from red to black phosphorus at 700 °C and 1.5 GPa is demonstrated. The synthesized ≈50 nm thick BP thin films are polycrystalline with a crystal domain size ranging from 40 to 70 µm long, as indicated by Raman mapping and infrared extinction spectroscopy. At room temperature, field-effect mobility of the synthesized BP thin film is found to be around 160 cm V s along armchair direction and reaches up to about 200 cm V s at around 90 K. Moreover, red phosphorus (RP) covered by exfoliated hexagonal boron nitride (hBN) before conversion shows atomically sharp hBN/BP interface and perfectly layered BP after the conversion. This demonstration represents a critical step toward the future realization of large scale, high-quality BP devices and circuits.
黑磷（BP）由于其独特的物理性质，最近引起了广泛关注。目前，高质量的少层和薄膜 BP 主要通过机械剥离法制备，限制了其在未来应用中的潜力。在这里，通过在 700°C 和 1.5 GPa 下将红磷转化为黑磷，在 5mm 蓝宝石衬底上成功合成了高结晶度的薄膜 BP。合成的 ≈50nm 厚的 BP 薄膜是多晶的，其晶粒尺寸范围从 40 到 70µm 长，这可以通过拉曼映射和红外消光光谱来证明。在室温下，合成的 BP 薄膜的场效应迁移率在扶手椅方向约为 160cmV s，在 90K 左右可达约 200cmV s。此外，在转化之前，覆盖有剥离的六方氮化硼（hBN）的红磷（RP）在转化后显示出原子级锋利的 hBN/BP 界面和完全分层的 BP。这一演示代表了向未来实现大规模、高质量 BP 器件和电路迈出的关键一步。
