EAGER: Black Phosphorus For Tunable Wide Bandwidth Sensor Arrays

摘要：用于可调谐宽带传感器阵列的黑磷纳米碳化物在过去的几十年里引起了研究人员的关注，他们使用的材料包括木桶球、碳纳米管、碳纳米纤维和石墨烯。这种丰富的纳米碳选择是可能的，因为纳米碳的不同晶体结构，其中一种形式是二维(2D)石墨烯，一种层状材料。二维石墨烯使研究人员能够探索其他2D层状材料，如过渡金属二卤化物、各种氧化物、氮化物和粘土。除了碳以外，最近增加的一种材料是磷，它在固态结构上也显示出很大的多样性，从正交黑磷、立方白磷、单斜紫磷、纤维红磷和无定形红磷。最近，磷的层状结构引起了人们的极大关注，特别是具有独特的折叠蜂窝晶格的黑色磷。然而，与石墨不同的是，黑磷是一种直接带状半导体，使其成为光电子和传感应用的一种有吸引力的材料。这项工作的重点是了解黑磷的有趣的电学和光电性质，并利用这种材料开发新型的光电传感器件。黑磷的直接带隙很窄，只有0.3 eV，这与大多数过渡金属二卤化物的间接带隙要高得多不同，这表明黑磷在近红外和中红外区域具有潜在的传感和探测器应用前景。此外，还可以通过控制膜厚来控制黑磷的带隙，带隙随着层数的减少而增大，单层磷的带隙最大可达2 eV。因此，设计具有不同层数的黑磷器件阵列中的层数应该能够在较宽的光谱范围内进行光检测。我们将利用黑磷的奇异特性，将这种新型材料与二硫化钼(MoS2)相结合，展示高性能的可调传感器阵列，其工作范围从可见光到红外(IR)。该方案的新颖之处在于利用了黑磷的可调谐带隙特性及其载流子的高迁移率来实现快速响应时间探测器，同时，二维(2D)van der Waals异质结之间原子锐利的界面应该可以通过减少困扰掺杂梯度结性能的暗电流来产生超灵敏探测器。

Abstract: Black Phosphorus for Tunable Wide-bandwidth Sensor ArraysNanocarbons have captured the attention of researchers over the past several decades with materials such as buckeyballs, carbon nanotubes, carbon nanofibers and graphene. This rich variety of nanocarbon choices is possible due to the diverse crystalline structures of nancarbons, one form of which is two-dimensional (2D) graphene, a layered material. Two-dimensional graphene has enabled researchers to explore other 2D layered materials, such as the transition metal dichalcogenides, a wide variety of oxides and nitrides and clays. A recent addition to the suite of materials beyond carbon is phosphorus which also shows great diversity in its structures in the solid state, ranging from orthorhombic black phosphorus, cubic white phosphorus, monoclinic violet phosphorus, fibrous red phosphorus and amorphous red phosphorus. Recently, a great deal of attention has been paid to the layered form of phosphorus, specifically black phosphorus which has a unique puckered honeycomb lattice. However, unlike graphite, black phosphorus is a direct band semiconductor in the bulk making it an attractive material for optoelectronics and sensing applications. The focus of the work proposed here is to understand the intriguing electronic and optoelectronic properties of black phosphorous and to develop novel optoelectronic sensing devices from this material. Black phosphorus has a narrow direct band gap of 0.3 eV in the bulk, unlike most of the transition metal dichalcogenides which have much higher, indirect band gaps, suggesting that black phosphorus has prospects for sensing and detector applications targeted for the near IR and mid-IR regimes. Moreover, the band gap of black phosphorus can be engineered through control of layer thickness; the band gap increases with decreasing layer number, reaching 2 eV for single layer phosphorene. Therefore, engineering the layer number in arrays of black phosphorus devices with varying layer number should enable photo-detection over a broad spectral range. We will utilize the exotic properties of black phosphorus and integrate this novel material with molybdenum disulphide (MoS2) to demonstrate high performance tunable sensor arrays operational over a wide spectral regime from the visible to the infrared (IR). The novel features of this proposal are to capitalize on the tunable band gap properties of black phosphorus, the high mobility of its carriers to enable fast response time detectors, and at the same time, the atomically sharp interfaces between two-dimensional (2D) van der Waals heterostructures should yield ultra-sensitive detectors by reducing dark currents that plague the performance of doped-graded junctions.