Photodetectors converting light signals into detectable photocurrents are ubiquitously in use today.To improve the compactness and performance of next-generation devices and systems,low dimensional materials provide r...Photodetectors converting light signals into detectable photocurrents are ubiquitously in use today.To improve the compactness and performance of next-generation devices and systems,low dimensional materials provide rich physics to engineering the light-matter interaction.Photodetectors based on two-dimensional(2D)material van der Waals heterostructures have shown high responsivity and compact integration capability,mainly in the visible range due to their intrinsic bandgap.The spectral region of near-infrared(NIR)is technologically important,featuring many data communication and sensing applications.While some initial NIR 2D material-based detectors have emerged,demonstrations of doping-junction-based 2D material photodetectors with the capability to harness the charge-separation photovoltaic effect are yet outstanding.Here,we demonstrate a 2D p-n van der Waals heterojunction photodetector constructed by vertically stacking p-type and n-type indium selenide(In Se)flakes.This heterojunction charge-separation-based photodetector shows a threefold enhancement in responsivity in the NIR spectral region(980 nm)as compared to photoconductor detectors based on p-or n-only doped In Se.We show that this junction device exhibits self-powered photodetection operation,exhibits few p A-low dark currents,and is about 3-4 orders of magnitude more efficient than the state-of-the-art foundry-based devices.Such capability opens doors for low noise and low photon flux photodetectors that do not rely on external gain.We further demonstrate millisecond response rates in this sensitive zero-bias voltage regime.Such sensitive photodetection capability in the technologically relevant NIR wavelength region at low form factors holds promise for several applications including wearable biosensors,three-dimensional(3D)sensing,and remote gas sensing.展开更多
基金Air Force Office of Scientific Research(FA9550-20-1-0193)National Institute of Standards and Technology(70NANB19H138)。
文摘Photodetectors converting light signals into detectable photocurrents are ubiquitously in use today.To improve the compactness and performance of next-generation devices and systems,low dimensional materials provide rich physics to engineering the light-matter interaction.Photodetectors based on two-dimensional(2D)material van der Waals heterostructures have shown high responsivity and compact integration capability,mainly in the visible range due to their intrinsic bandgap.The spectral region of near-infrared(NIR)is technologically important,featuring many data communication and sensing applications.While some initial NIR 2D material-based detectors have emerged,demonstrations of doping-junction-based 2D material photodetectors with the capability to harness the charge-separation photovoltaic effect are yet outstanding.Here,we demonstrate a 2D p-n van der Waals heterojunction photodetector constructed by vertically stacking p-type and n-type indium selenide(In Se)flakes.This heterojunction charge-separation-based photodetector shows a threefold enhancement in responsivity in the NIR spectral region(980 nm)as compared to photoconductor detectors based on p-or n-only doped In Se.We show that this junction device exhibits self-powered photodetection operation,exhibits few p A-low dark currents,and is about 3-4 orders of magnitude more efficient than the state-of-the-art foundry-based devices.Such capability opens doors for low noise and low photon flux photodetectors that do not rely on external gain.We further demonstrate millisecond response rates in this sensitive zero-bias voltage regime.Such sensitive photodetection capability in the technologically relevant NIR wavelength region at low form factors holds promise for several applications including wearable biosensors,three-dimensional(3D)sensing,and remote gas sensing.
