Highly Efficient and Air-Stable Infrared Photodetector Based on 2D Layered Graphene–Black Phosphorus Heterostructure

5 years ago

Highly Efficient and Air-Stable Infrared Photodetector Based on 2D Layered Graphene–Black Phosphorus Heterostructure

Yan Liu, Shaojuan Li, Yuerui Lu, Yupeng Zhang, Yusheng Wang, Haoran Mu, Shenghuang Lin, Weiliang Ma, Wenzhi Yu, Si Xiao, Han Zhang, Tian Sun, Cheng-Wei Qiu, Qiaoliang Bao, Bannur Nanjunda Shivananju

The presence of a direct band gap and high carrier mobility in few-layer black phosphorus (BP) offers opportunities for using this material for infrared (IR) light detection. However, the poor air stability of BP and its large contact resistance with metals pose significant challenges to the fabrication of highly efficient IR photodetectors with long lifetimes. In this work, we demonstrate a graphene–BP heterostructure photodetector with ultrahigh responsivity and long-term stability at IR wavelengths. In our device architecture, the top layer of graphene functions not only as an encapsulation layer but also as a highly efficient transport layer. Under illumination, photoexcited electron–hole pairs generated in BP are separated and injected into graphene, significantly reducing the Schottky barrier between BP and the metal electrodes and leading to efficient photocurrent extraction. The graphene–BP heterostructure phototransistor exhibits a long-term photoresponse at near-infrared wavelength (1550 nm) with an ultrahigh photoresponsivity (up to 3.3 × 10³ A W^–1), a photoconductive gain (up to 1.13 × 10⁹), and a rise time of about 4 ms. Considering the thickness-dependent band gap in BP, this material represents a powerful photodetection platform that is able to sustain high performance in the IR wavelength regime with potential applications in remote sensing, biological imaging, and environmental monitoring.

Publisher URL: http://dx.doi.org/10.1021/acsami.7b09889

DOI: 10.1021/acsami.7b09889