Graphene/black phosphorus heterostructured photodetector

• Published in: Solid-state electronics Vol. 144; pp. 86 - 89
• Main Authors: Xu, Jiao, Song, Young Jae, Park, Jin-Hong, Lee, Sungjoo
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2018
• Subjects: Black phosphorus; Graphene; Photodetector; Graphene; Photodetector; Black phosphorus
• ISSN: 0038-1101; 1879-2405
• DOI: 10.1016/j.sse.2018.03.007

•Graphene/black phosphorus (BP) heterostructure photodetectors work from visible to NIR range.•Detection mechanism is based on a photogating effect.•High photoresponsivities come from the prolonged photocarrier lifetime and graphene high carrier mobility. Graphene photodetectors exhibit a low photoresponsivity due to their weak light absorbance. In this study, we fabricated a graphene/black phosphorus (BP) heterostructure, in which the multilayer BP flake with a ∼0.3 eV direct band gap functions as an enhanced light-absorption material. Further, the photoexcited electrons are trapped in the trap states of the BP, which creates a photogating effect and causes holes to flow into the graphene layer driven by the built-in potential between BP and graphene. The photocarrier lifetime is therefore prolonged by trapping, and as a result of the high carrier mobility of graphene, the holes that transfer into the graphene channel can travel through the circuit before they recombine with trapped electrons. These combined effects result in a high photoresponsivity: 55.75 A/W at λ = 655 nm, 1.82 A/W at λ = 785 nm, and 0.66 A/W at λ = 980 nm.