Highly Sensitive, Fast Graphene Photodetector with Responsivity $>10^6$ A/W Using Floating Quantum Well Gate

Abstract

Graphene, owing to its zero bandgap electronic structure, is promising as an absorption material for ultra-wideband photodetection applications. However, graphene-absorption based detectors inherently suffer from poor responsivity due to 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 purpose, 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 ultra-fast inter-layer transfer to a floating monolayer MoS${}_2$ quantum well providing strong quantum confined photogating effect. The photodetector shows a responsivity of $4.4\times 10^6$ A/W at 30 fW incident power, outperforming photodetectors reported till date where graphene is used as light absorption material by several orders. In addition, the proposed photodetector exhibits an extremely low noise equivalent power ($NEP$) of $<4$ fW/$\sqrt{Hz}$ and a fast response ($\sim$ milliseconds) with zero reminiscent photocurrent. The findings are attractive towards the demonstration of graphene-based highly sensitive, fast, broadband photodetection technology.

References in corpus (23)

• Universal Dynamic Conductivity and Quantized Visible Opacity of Suspended Graphene
• Ultrafast graphene photodetector
• Graphene photodetectors for high-speed optical communications
• Ultrafast Charge Transfer in Atomically Thin MoS2/WS2 Heterostructures
• Observation of giant bandgap renormalization and excitonic effects in a monolayer transition metal dichalcogenide semiconductor
• Strong Photoluminescence Enhancement of MoS2 through Defect Engineering and Oxygen Bonding
• Hot Carrier-Assisted Intrinsic Photoresponse in Graphene
• Microcavity-integrated graphene photodetector
• Ultrafast Optical-Pump Terahertz-Probe Spectroscopy of the Carrier Relaxation and Recombination Dynamics in Epitaxial Graphene
• Mechanisms of photoconductivity in atomically thin MoS2
• Picosecond photoresponse in van der Waals heterostructures
• Photoconductivity of biased graphene
• Carrier Recombination and Generation Rates for Intravalley and Intervalley Phonon Scattering in Graphene
• Optical properties of atomically thin transition metal dichalcogenides: Observations and puzzles
• Plasmonically enhanced graphene photodetector featuring 100 GBd, high-responsivity and compact size
• Graphene-based, mid-infrared, room-temperature pyroelectric bolometers with ultrahigh temperature coefficient of resistance
• High performance bilayer-graphene Terahertz detectors
• Electron-Hole Generation and Recombination Rates for Coulomb Scattering in Graphene
• Hybrid graphene tunneling photoconductor with interface engineering towards fast photoresponse and high responsivity
• Zeeman Splitting and Inverted Polarization of Biexciton Emission in Monolayer WS2
• Singlet and triplet trions in WS${}_2$ monolayer encapsulated in hexagonal boron nitride
• Direct observation of giant binding energy modulation of exciton complexes in monolayer MoSe${}_2$
• Free-space graphene/silicon photodetectors operating at 2 micron

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