2019/07/26 by Krishna Murali, Nithin Abraham, Sarthak Das +2
Engineering · Materials Science · Physics and Astronomy · #2D Materials and Applications #Graphene #Graphene research and applications #Materials science #Nanotechnology #Nanowire Synthesis and Applications #Optoelectronics #Photodetector #Physics #Quantum #Quantum dot #Quantum mechanics #Responsivity #cond-mat.mes-hall #cond-mat.mtrl-sci #physics.app-ph
paper · pdf · doi:10.1021/acsami.9b06835
published as ACS Applied Materials & Interfaces, 2019
openalex publication_date 2019/07/26 · openalex created_date 2019/08/13 · arxiv created 2019/08/19 · arxiv updated 2019/08/20 · openalex updated_date 2026/08/05
Graphene, owing to its zero-band-gap electronic structure, is promising as an absorption material for ultra-wideband photodetection applications. However, graphene-absorption-based detectors inherently suffer from poor responsivity because of weak absorption and fast photocarrier recombination, limiting their viability for low-intensity light detection. Here, we use a graphene/WS 2 /MoS 2 vertical heterojunction to demonstrate a highly sensitive photodetector, where the graphene layer serves dual purposes, namely, as the light absorption layer and also as the carrier conduction channel, thus maintaining the broadband nature of the photodetector. A fraction of the photoelectrons in graphene encounter ultrafast interlayer transfer to a floating monolayer MoS 2 quantum well, providing a strong quantum-confined photogating effect. The photodetector shows a responsivity of 4.4 × 10 6 A/W at 30 fW incident power, outperforming photodetectors reported till date where graphene is used as a light absorption material by several orders. In addition, the proposed photodetector exhibits an extremely low noise equivalent power of <4 fW/ and a fast response (∼milliseconds) with zero reminiscent photocurrent. The findings are attractive toward the demonstration of a graphene-based highly sensitive, fast, broadband photodetection technology.