Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, 117583, Singapore.
Centre for Advanced 2D Materials, National University of Singapore, 6 Science Drive 2, Singapore, 117543, Singapore.
Adv Mater. 2018 Feb;30(6). doi: 10.1002/adma.201705039. Epub 2017 Dec 21.
Photodetectors with broadband detection capability are desirable for sensing applications in the coming age of the internet-of-things. Although 2D layered materials (2DMs) have been actively pursued due to their unique optical properties, by far only graphene and black arsenic phosphorus have the wide absorption spectrum that covers most molecular vibrational fingerprints. However, their reported responsivity and response time are falling short of the requirements needed for enabling simultaneous weak-signal and high-speed detections. Here, a novel 2DM, black phosphorous carbide (b-PC) with a wide absorption spectrum up to 8000 nm is synthesized and a b-PC phototransistor with a tunable responsivity and response time at an excitation wavelength of 2004 nm is demonstrated. The b-PC phototransistor achieves a peak responsivity of 2163 A W and a shot noise equivalent power of 1.3 fW Hz at 2004 nm. In addition, it is shown that a response time of 0.7 ns is tunable by the gating effect, which renders it versatile for high-speed applications. Under the same signal strength (i.e., excitation power), its performance in responsivity and detectivity in room temperature condition is currently ahead of recent top-performing photodetectors based on 2DMs that operate with a small bias voltage of 0.2 V.
对于即将到来的物联网时代的传感应用而言，具有宽带检测能力的光电探测器是非常理想的。尽管二维层状材料（2DMs）由于其独特的光学特性而被积极研究，但迄今为止，只有石墨烯和黑砷磷具有覆盖大多数分子振动指纹的宽吸收光谱。然而，它们的报道响应率和响应时间都无法满足同时进行弱信号和高速检测的要求。在这里，合成了一种新型的二维层状材料黑磷碳化硅（b-PC），其吸收光谱宽达 8000nm，并展示了一种在 2004nm 激发波长下可调谐响应率和响应时间的 b-PC 光电晶体管。b-PC 光电晶体管在 2004nm 处实现了 2163A/W 的峰值响应率和 1.3fW Hz 的噪声等效功率。此外，通过栅极效应可以将其响应时间调至 0.7ns，这使其适用于高速应用。在相同的信号强度（即激发功率）下，其在室温条件下的响应率和探测率的性能目前超过了基于工作在 0.2V 小偏置电压下的 2DMs 的最新高性能光电探测器。
