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 detec-tors have emerged,demonstrations of doping-j unction-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(InSe)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 InSe.We show that this junction device exhibits self-powered photodetection operation,exhibits few pA-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 sensi-tive 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.

CHANDRAMAN PATIL;CHAOBO DONG;HAO WANG;BEHROUZ MOVAHHED NOURI;SERGIY KRYLYUK;HUAIRUO ZHANG;ALBERT V.DAVYDOV;HAMED DALIR;VOLKER J.SORGER

Department of Electrical and Computer Engineering,George Washington University,Washington,D.C.20052,USA;Optelligence LLC,Upper Marlboro,Maryland 20772,USA;Materials Science and Engineering Division,National Institute of Standards and Technology,Gaithersburg,Maryland 20899,USA;Theiss Research,Inc.,La Jolla,California 92037,USA

光子学研究（英文）

[1]CHANDRAMAN PATIL;CHAOBO DONG;HAO WANG;BEHROUZ MOVAHHED NOURI;SERGIY KRYLYUK;HUAIRUO ZHANG;ALBERT V.DAVYDOV;HAMED DALIR;VOLKER J.SORGER-.Self-driven highly responsive p-n junction InSe heterostructure near-infrared light detector)[J].光子学研究（英文）,2022(07):前插1-前插9

photocurrents,unction,photoconductor

Self,driven,highly,responsive,InSe,near,infrared,light,Photodetectors,converting,signals,into,detectable,ubiquitously,use,today,To,improve,compactness,performance,next,generation,devices,systems,low,dimensional,materials,provide,rich,physics,engineering,matter,interaction,two,2D,Waals,heterostructures,have,shown,responsivity,integration,capability,mainly,visible,range,due,their,intrinsic,bandgap,spectral,region,NIR,technologically,important,featuring,many,data,communication,sensing,applications,While,some,initial,emerged,demonstrations,doping,photodetectors,harness,charge,separation,photovoltaic,effect,yet,outstanding,Here,demonstrate,heterojunction,constructed,by,vertically,stacking,type,indium,selenide,flakes,This,shows,threefold,enhancement,compared,only,doped,We,that,this,exhibits,self,powered,photodetection,operation,few,pA,dark,about,orders,magnitude,more,efficient,than,state,art,foundry,Such,opens,doors,noise,photon,flux,not,rely,external,gain,further,millisecond,response,rates,sensitive,zero,bias,voltage,regime,relevant,wavelength,factors,holds,promise,several,including,wearable,biosensors,remote,gas

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