Graphene is a very attractive material for broadband photodetection in hyperspectral imaging and sensing systems.However,its potential use has been hindered by tradeoffs between the responsivity,bandwidth,and operatio...Graphene is a very attractive material for broadband photodetection in hyperspectral imaging and sensing systems.However,its potential use has been hindered by tradeoffs between the responsivity,bandwidth,and operation speed of existing graphene photodetectors.Here,we present engineered photoconductive nanostructures based on goldpatched graphene nano-stripes,which enable simultaneous broadband and ultrafast photodetection with high responsivity.These nanostructures merge the advantages of broadband optical absorption,ultrafast photocarrier transport,and carrier multiplication within graphene nano-stripes with the ultrafast transport of photocarriers to gold patches before recombination.Through this approach,high-responsivity operation is realized without the use of bandwidth-limiting and speed-limiting quantum dots,defect states,or tunneling barriers.We demonstrate highresponsivity photodetection from the visible to infrared regime(0.6 A/W at 0.8μm and 11.5 A/W at 20μm),with operation speeds exceeding 50 GHz.Our results demonstrate improvement of the response times by more than seven orders of magnitude and an increase in bandwidths of one order of magnitude compared to those of higherresponsivity graphene photodetectors based on quantum dots and tunneling barriers.展开更多
Transition metal dichalcogenides(TMDCs)are promising candidates for future optoelectronic devices accounting for their high carrier mobility and excellent quantum efficiency.However,the limited light absorption effici...Transition metal dichalcogenides(TMDCs)are promising candidates for future optoelectronic devices accounting for their high carrier mobility and excellent quantum efficiency.However,the limited light absorption efficiency in atomically thin layers significantly hinders photocarrier generation,thereby impairing the optoelectronic performance and hindering practical applications.Herein,we successfully synthesized In_(2)Se_(3)/WSe_(2) heterostructures through a typical two-step chemical vapor deposition(CVD)method.The In_(2)Se_(3) nanosheet with strong light absorption capability,serving as the light absorption layer,was integrated with the monolayer WSe_(2),enhancing the photosensitivity of WSe_(2) significantly.Upon laser irradiation with a wavelength of 520 nm,the In_(2)Se_(3)/WSe_(2) heterostructure device shows an ultrahigh photoresponsivity with a value as high as 2333.5 A/W and a remarkable detectivity reaching up to 6.7×10^(12) Jones,which is the highest among almost the reported TMDCs-based heterostructures grown via CVD even some fabricated by mechanical exfoliation(ME).Combing the advantages of CVD method such as large scale,high yield,and clean interface,the In_(2)Se_(3)/WSe_(2) heterostructures would provide a novel path for future high-performance optoelectronic device.展开更多
4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity m...4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity measurements were carried out at room temperature. The fabricated 4 μm-spacing device showed a very low dark current (0.25 pA at 5 V bias voltage), a typical responsivity of 0.103 A/W at 20 V, and a peak re-sponse wavelength at 290 nm. The fabricated devices held a high DUV to visible re-jection ratio of >103.展开更多
基金support from the Department of Energy(grant#DE-SC0016925)。
文摘Graphene is a very attractive material for broadband photodetection in hyperspectral imaging and sensing systems.However,its potential use has been hindered by tradeoffs between the responsivity,bandwidth,and operation speed of existing graphene photodetectors.Here,we present engineered photoconductive nanostructures based on goldpatched graphene nano-stripes,which enable simultaneous broadband and ultrafast photodetection with high responsivity.These nanostructures merge the advantages of broadband optical absorption,ultrafast photocarrier transport,and carrier multiplication within graphene nano-stripes with the ultrafast transport of photocarriers to gold patches before recombination.Through this approach,high-responsivity operation is realized without the use of bandwidth-limiting and speed-limiting quantum dots,defect states,or tunneling barriers.We demonstrate highresponsivity photodetection from the visible to infrared regime(0.6 A/W at 0.8μm and 11.5 A/W at 20μm),with operation speeds exceeding 50 GHz.Our results demonstrate improvement of the response times by more than seven orders of magnitude and an increase in bandwidths of one order of magnitude compared to those of higherresponsivity graphene photodetectors based on quantum dots and tunneling barriers.
基金support from the following funding:the National Key R&D Program of China(No.2022YFA1204300)the National Natural Science Foundation of China(Nos.62104066,52221001,62090035,U19A2090,U22A20138 and 51902098)+5 种基金the Natural Science Foundation of Hunan Province(No.2021JJ20016)the Science and Technology Innovation Program of Hunan Province(Nos.2021RC3061 and 2020RC2028)the Key Program of Science and Technology Department of Hunan Province(Nos.2019XK2001 and 2020XK2001)the Open Project Program of Wuhan National Laboratory for Optoelectronics(No.2020WNLOKF016)the National Postdoctoral Program for Innovative Talents(No.BX2021094)the Postdoctoral Science Foundation of China(No.2020M680112).
文摘Transition metal dichalcogenides(TMDCs)are promising candidates for future optoelectronic devices accounting for their high carrier mobility and excellent quantum efficiency.However,the limited light absorption efficiency in atomically thin layers significantly hinders photocarrier generation,thereby impairing the optoelectronic performance and hindering practical applications.Herein,we successfully synthesized In_(2)Se_(3)/WSe_(2) heterostructures through a typical two-step chemical vapor deposition(CVD)method.The In_(2)Se_(3) nanosheet with strong light absorption capability,serving as the light absorption layer,was integrated with the monolayer WSe_(2),enhancing the photosensitivity of WSe_(2) significantly.Upon laser irradiation with a wavelength of 520 nm,the In_(2)Se_(3)/WSe_(2) heterostructure device shows an ultrahigh photoresponsivity with a value as high as 2333.5 A/W and a remarkable detectivity reaching up to 6.7×10^(12) Jones,which is the highest among almost the reported TMDCs-based heterostructures grown via CVD even some fabricated by mechanical exfoliation(ME).Combing the advantages of CVD method such as large scale,high yield,and clean interface,the In_(2)Se_(3)/WSe_(2) heterostructures would provide a novel path for future high-performance optoelectronic device.
文摘4H-SiC based metal-semiconductor-metal (MSM) photodetectors with diverse spacing were designed, fabricated, and characterized, in which nickel Schottky contacts were needed. Current-voltage and spectral responsivity measurements were carried out at room temperature. The fabricated 4 μm-spacing device showed a very low dark current (0.25 pA at 5 V bias voltage), a typical responsivity of 0.103 A/W at 20 V, and a peak re-sponse wavelength at 290 nm. The fabricated devices held a high DUV to visible re-jection ratio of >103.
