We demonstrate a high performance GaAs/AlGaAs-based quantum-well photodetector(QWP)device with a peak response frequency of 4.3 THz.The negative differential resistance(NDR)phenomenon is found in the dark currentvolta...We demonstrate a high performance GaAs/AlGaAs-based quantum-well photodetector(QWP)device with a peak response frequency of 4.3 THz.The negative differential resistance(NDR)phenomenon is found in the dark currentvoltage(I-V)curve in the current sweeping measurement mode,from which the breakdown voltage is determined.The photocurrent spectra and blackbody current responsivities at different voltages are measured.Based on the experimental data,the peak responsivity of 0.3 A/W(at 0.15 V,8 K)is derived,and the detection sensitivity is higher than 10^(11)Jones,which is in the similar level as that of the commercialized liquid-helium-cooled silicon bolometers.We attribute the high detection performance of the device to the small ohmic contact resistance of-2Ωand the big breakdown bias.展开更多
We demonstrate a wireless transmission link at 3.9 THz over a distance of 0.5 m by employing a terahertz （Hz） quantum-cascade laser （QCL） and a THz quantum-well photodetector （QWP）. We make direct voltage modula...We demonstrate a wireless transmission link at 3.9 THz over a distance of 0.5 m by employing a terahertz （Hz） quantum-cascade laser （QCL） and a THz quantum-well photodetector （QWP）. We make direct voltage modulation of the THz QCL and use a spectral-matched THz QWP to detect the modulated THz light from the laser. The small signal model and a direct voltage modulation scheme of the laser are presented. A square wave up to 30 MHz is added to the laser and detected by the THz detector. The bandwidth limit of the wireless link is also discussed.展开更多
For eventually providing terahertz science with compact and convenient devices,terahertz (1～10THz) quantum-well photodetectors and quantum-cascade lasers are investigated.The design and projected detector performance...For eventually providing terahertz science with compact and convenient devices,terahertz (1～10THz) quantum-well photodetectors and quantum-cascade lasers are investigated.The design and projected detector performance are presented together with experimental results for several test devices,all working at photon energies below and around optical phonons.Background limited infrared performance (BLIP) operations are observed for all samples (three in total),designed for different wavelengths.BLIP temperatures of 17,13,and 12K are achieved for peak detection frequencies of 9.7THz(31μm),5.4THz(56μm),and 3.2THz(93μm),respectively.A set of THz quantum-cascade lasers with identical device parameters except for doping concentration is studied.The δ-doping density for each period varies from 3.2×1010 to 4.8×1010cm-2.We observe that the lasing threshold current density increases monotonically with doping concentration.Moreover,the measurements for devices with different cavity lengths provide evidence that the free carrier absorption causes the waveguide loss also to increase monotonically.Interestingly the observed maximum lasing temperature is best at a doping density of 3.6×1010cm-2.展开更多
With the rapid development of terahertz technology,terahertz detectors are expected to play a key role in diverse areas such as homeland security and imaging,materials diagnostics,biology,medical sciences,and communic...With the rapid development of terahertz technology,terahertz detectors are expected to play a key role in diverse areas such as homeland security and imaging,materials diagnostics,biology,medical sciences,and communication.Whereas self-powered,rapid response,and room temperature terahertz photodetectors are confronted with huge challenges.Here,we report a novel rapid response and self-powered terahertz photothermoelectronic(PTE)photodetector based on a lowdimensional material:palladium selenide(Pd Se_(2)).An order of magnitude performance enhancement was observed in photodetection based on PdSe_(2)/graphene heterojunction that resulted from the integration of graphene and enhanced the Seebeck effect.Under 0.1-THz and 0.3-THz irradiations,the device displays a stable and repeatable photoresponse at room temperature without bias.Furthermore,rapid rise(5.0μs)and decay(5.4μs)times are recorded under 0.1-THz irradiation.Our results demonstrate the promising prospect of the detector based on Pd Se2 in terms of air-stable,suitable sensitivity and speed,which may have great application in terahertz detection.展开更多
基金Project supported by the National Key R&D Program of China(Grant No.2017YFF0106302)the National Basic Research Program of of China(Grant No.2014CB339803)+1 种基金the National Natural Science Foundation of China(Grant Nos.61404150,61405233,and 61604161)the Shanghai Municipal Commission of Science and Technology,China(Grant Nos.15JC1403800,17ZR1448300,and 17YF1429900)
文摘We demonstrate a high performance GaAs/AlGaAs-based quantum-well photodetector(QWP)device with a peak response frequency of 4.3 THz.The negative differential resistance(NDR)phenomenon is found in the dark currentvoltage(I-V)curve in the current sweeping measurement mode,from which the breakdown voltage is determined.The photocurrent spectra and blackbody current responsivities at different voltages are measured.Based on the experimental data,the peak responsivity of 0.3 A/W(at 0.15 V,8 K)is derived,and the detection sensitivity is higher than 10^(11)Jones,which is in the similar level as that of the commercialized liquid-helium-cooled silicon bolometers.We attribute the high detection performance of the device to the small ohmic contact resistance of-2Ωand the big breakdown bias.
基金supported by the National 973 Program of China(No.2014CB339803)the National 863 Program of China(No.2011AA010205)+4 种基金the National Natural Science Foundation of China(Nos.61131006,61321492,61176086,61204135,and 61306066)the Major National Development Project of Scientific Instrument and Equipment(No.2011YQ150021)the National Science and Technology Major Project(No.2011ZX02707)the Major Project(No.YYYJ1123-1)the International Collaboration and Innovation Program on High Mobility Materials Engineering of the Chinese Academy of Sciences and the Shanghai Municipal Commission of Science and Technology(No.13ZR1464600)
文摘We demonstrate a wireless transmission link at 3.9 THz over a distance of 0.5 m by employing a terahertz （Hz） quantum-cascade laser （QCL） and a THz quantum-well photodetector （QWP）. We make direct voltage modulation of the THz QCL and use a spectral-matched THz QWP to detect the modulated THz light from the laser. The small signal model and a direct voltage modulation scheme of the laser are presented. A square wave up to 30 MHz is added to the laser and detected by the THz detector. The bandwidth limit of the wireless link is also discussed.
文摘For eventually providing terahertz science with compact and convenient devices,terahertz (1～10THz) quantum-well photodetectors and quantum-cascade lasers are investigated.The design and projected detector performance are presented together with experimental results for several test devices,all working at photon energies below and around optical phonons.Background limited infrared performance (BLIP) operations are observed for all samples (three in total),designed for different wavelengths.BLIP temperatures of 17,13,and 12K are achieved for peak detection frequencies of 9.7THz(31μm),5.4THz(56μm),and 3.2THz(93μm),respectively.A set of THz quantum-cascade lasers with identical device parameters except for doping concentration is studied.The δ-doping density for each period varies from 3.2×1010 to 4.8×1010cm-2.We observe that the lasing threshold current density increases monotonically with doping concentration.Moreover,the measurements for devices with different cavity lengths provide evidence that the free carrier absorption causes the waveguide loss also to increase monotonically.Interestingly the observed maximum lasing temperature is best at a doping density of 3.6×1010cm-2.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61521005,61875217,91850208,61474130,and 62075230)the Natural Science Foundation of Shanghai,China(Grant Nos.19ZR1465400,21ZR1473800+1 种基金20142200600)the Fund from Zhejiang Laboratory(Grant No.2021MB0AB01)。
文摘With the rapid development of terahertz technology,terahertz detectors are expected to play a key role in diverse areas such as homeland security and imaging,materials diagnostics,biology,medical sciences,and communication.Whereas self-powered,rapid response,and room temperature terahertz photodetectors are confronted with huge challenges.Here,we report a novel rapid response and self-powered terahertz photothermoelectronic(PTE)photodetector based on a lowdimensional material:palladium selenide(Pd Se_(2)).An order of magnitude performance enhancement was observed in photodetection based on PdSe_(2)/graphene heterojunction that resulted from the integration of graphene and enhanced the Seebeck effect.Under 0.1-THz and 0.3-THz irradiations,the device displays a stable and repeatable photoresponse at room temperature without bias.Furthermore,rapid rise(5.0μs)and decay(5.4μs)times are recorded under 0.1-THz irradiation.Our results demonstrate the promising prospect of the detector based on Pd Se2 in terms of air-stable,suitable sensitivity and speed,which may have great application in terahertz detection.
