Recently rediscovered black phosphorus is a layered semiconductor with promising electronic and photonic properties. Dynamic control of its bandgap can allow for the exploration of new physical phenomena. However, theoretical investigations and photoemission spectroscopy experiments indicate that in its few-layer form, an exceedingly large electric field in the order of several volts per nanometre is required to effectively tune its bandgap, making the direct electrical control unfeasible. Here we reveal the unique thickness-dependent bandgap tuning properties in intrinsic black phosphorus, arising from the strong interlayer electronic-state coupling. Furthermore, leveraging a 10 nm-thick black phosphorus, we continuously tune its bandgap from ∼300 to below 50 meV, using a moderate displacement field up to 1.1 V nm−1. Such dynamic tuning of bandgap may not only extend the operational wavelength range of tunable black phosphorus photonic devices, but also pave the way for the investigation of electrically tunable topological insulators and semimetals.
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机译：最近重新发现的黑磷是具有有前途的电子和光子特性的层状半导体。动态控制其带隙可以允许探索新的物理现象。然而，理论研究和光发射光谱实验表明，以其几层形式，为了有效地调节其带隙需要大约几伏特/纳米的非常大的电场，使得直接电控制是不可行的。在这里，我们揭示了固有的黑磷中依赖于厚度的带隙微调特性，这是由强的层间电子状态耦合引起的。此外，我们利用一个10 nm厚的黑磷，利用高达1.1 V nm -1 的中等位移场，将其能带隙从〜300连续调谐到约50meV。带隙的这种动态调谐不仅可以扩展可调谐黑磷光子器件的工作波长范围，而且可以为研究电可调谐拓扑绝缘体和半金属铺平道路。
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