Towards tunable and scalable black phosphorus photodetectors

黑磷是磷的一种稳定的同素异形体，它呈现出一种层状结构，可以像石墨烯一样剥离到单一的单层。这种元素2D半导体提供了几个独特的特征：非常高的载流子迁移率，各向异性的能带结构，以及有效地吸收光的直接带隙。此外，BP还提供了其他任何2D或块状材料无法比拟的两个特性：可通过样品厚度从中红外到可见光的可调直接带隙，以及通过外加电场动态调整带隙的能力。这些特点为开发低成本的光电探测器提供了独特的机会，这些探测器在技术上具有重要意义的红外光谱区域具有更高的响应度和工作频率。与世界上最重要的光电探测器制造商之一Excelitas密切合作，我们将开发一系列基于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，我们将通过使用光学亚表面来提高其灵敏度，最后我们将利用BP纳米颗粒的溶液处理来开发低成本的大面积BP探测器。黑磷探测器在通信、光谱学、测距和热成像等领域具有潜在的应用前景。在本项目的背景下，我们将特别将BP可调探测器作为潜在的示踪气体传感器进行基准测试。

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.