Towards tunable and scalable black phosphorus photodetectors

黑磷是磷的一种稳定的同素异形体，呈层状结构，可以像石墨烯一样剥离，只剩下一层。这种基本的二维半导体具有几个独特的特点：非常高的载流子迁移率，各向异性的能带结构，以及有效吸收光的直接间隙。此外，BP还提供了任何其他二维或块状材料无法比拟的两个特性：通过样品厚度可调节中红外到可见光的直接带隙，以及通过外加电场动态调节带隙的能力。这些特点为低成本光电探测器的发展提供了独特的机会，在技术上重要的红外光谱区域具有增强的响应性和工作频率。我们将与世界上最重要的光电探测器制造商之一Excelitas密切合作，开发一系列基于BP的红外光电探测器架构。特别是，我们将开发电场可调谐的BP光电探测器，将BP的固有光谱范围扩展到4微米以上，我们将通过光学超表面来提高它们的灵敏度，最后我们将开发低成本的大面积BP探测器，使用基于溶液的BP纳米颗粒处理。黑磷探测器将在电信、光谱学、测距和热成像方面有潜在的应用。在这个项目的背景下，我们将特别基准BP可调探测器作为潜在的痕量气体传感器。

Black phosphorus is a stable allotrope of phosphorus that exhibits a layered structure that can be exfoliated,like graphene, down to a single monolayer. This elemental 2D semiconductor offers several distinctivefeatures: remarkably high carrier mobilities, an anisotropic band structure, and a direct gap that efficientlyabsorbs light. In addition, BP offers two characteristics unmatched by any other 2D or bulk materials: a tunabledirect bandgap from the mid-infrared to the visible via the sample thickness and the ability to dynamically tunethe gap through an applied electric field. These characteristics present unique opportunities for thedevelopment of low-cost photodetectors with enhanced responsivities and operating frequencies in thetechnologically important infrared region of the spectrum. In close partnership with Excelitas, one of the mostimportant photodetector manufacturers in the world, we will develop a number of infrared photodetectorarchitectures based on BP. In particular, we will develop electric-field tunable BP photodetectors to extend theintrinsic spectral range of BP beyond 4 microns, we will enhance their sensitivity by using optical metasurfacesand finally we will develop low-cost large-area BP detectors using solution-based processing of BPnanoparticles. Black phosphorus detectors will have potential applications in telecommunications,spectroscopy, range finding and thermal imaging. Within the context of this Project, we will specificallybenchmark BP tunable detectors as potential trace gas sensors.