The superconducting nanowire single photon detector（SNSPD） draws much attention because of its attractive performance at ultra violet, visible, and nearinfrared wavelengths, and it can be widespread in quantum infor...The superconducting nanowire single photon detector（SNSPD） draws much attention because of its attractive performance at ultra violet, visible, and nearinfrared wavelengths, and it can be widespread in quantum information technologies. However, how to increase the absorption which can dramatically increase the quantum efficiency of the SNSPD is still a top research issue. In this study, the effect of incident medium and cavity material on the optical absorptance of cavity-integrated SNSPDs was systematically investigated using finite-element method. The simulation results demonstrate that for photons polarized parallel to nanowire orientation, even though the maximum absorptance of the nanowire is insensitive to cavity material,it does increase when the refractive index of incident medium decreases. For perpendicularly polarized photons, both incident medium and cavity material play significant roles,and the absorptance curves get closer to the parallel case as the refractive index of cavity material increases. Based on these results, two cavity-integrated SNSPDs with frontillumination structure which can enhance the absorptance for both parallel and perpendicular photons are proposed.Finally, a design to realize polarization-independent SNSPDs with high absorptance is presented.展开更多
Narrow bandgap non-fullerene acceptors(NFAs)are relevant as key materials components for the fabrication of near-infrared(NIR)organic solar cells(OSCs)and organic photodiodes(OPDs)thanks to their complementary absorpt...Narrow bandgap non-fullerene acceptors(NFAs)are relevant as key materials components for the fabrication of near-infrared(NIR)organic solar cells(OSCs)and organic photodiodes(OPDs)thanks to their complementary absorption,tunable energy levels,and enhanced stability.However,high-performance NIR photodetectors are still scarce due to the absence of narrow bandgap NFAs.Herein,an asymmetric A-D-π-A type NFA,named ABTPV-S,with a broad optical absorption approaching 1,000 nm is designed and synthesized through integrating alkylthio side chains and a vinyleneπ-bridge.The optimal inverted OPD device exhibits an excellent performance with a photoresponsivity of 0.39 AW-1,a noise current of 2.25×10^(-14)A Hz^(-0.5),a specific detectivity(D*)of 3.43×10^(12)Jones at 840 nm,and linear dynamic range(LDR)of 140 d B.In addition,the rise and fall times for ABTPV-S-based OPDs also reach 1.07 and 0.71μs,respectively.ABTPV-S-based OPDs exhibit a high D*over 1012Jones at 950 nm,which is a competitive result for the self-powered photodiode-type NIR OPDs.These findings highlight the outstanding potential of asymmetric A-D-π-A type NIR NFAs for high-performance OPDs competing with their silicon counterparts.展开更多
基金financially supported by the China State Key Program for Basic Research (No. 2011CBA00304)Tsinghua University Initiative Scientific Research Program (No. 2010Z01010)the National Natural Science Foundation of China (Nos. 61106121 and 61174084)
文摘The superconducting nanowire single photon detector（SNSPD） draws much attention because of its attractive performance at ultra violet, visible, and nearinfrared wavelengths, and it can be widespread in quantum information technologies. However, how to increase the absorption which can dramatically increase the quantum efficiency of the SNSPD is still a top research issue. In this study, the effect of incident medium and cavity material on the optical absorptance of cavity-integrated SNSPDs was systematically investigated using finite-element method. The simulation results demonstrate that for photons polarized parallel to nanowire orientation, even though the maximum absorptance of the nanowire is insensitive to cavity material,it does increase when the refractive index of incident medium decreases. For perpendicularly polarized photons, both incident medium and cavity material play significant roles,and the absorptance curves get closer to the parallel case as the refractive index of cavity material increases. Based on these results, two cavity-integrated SNSPDs with frontillumination structure which can enhance the absorptance for both parallel and perpendicular photons are proposed.Finally, a design to realize polarization-independent SNSPDs with high absorptance is presented.
基金supported by the National Natural Science Foundation of China(21905137)the Basic Ability Improvement Project for Young and Middle-aged University Teachers of Guangxi(2022KY0256)。
文摘Narrow bandgap non-fullerene acceptors(NFAs)are relevant as key materials components for the fabrication of near-infrared(NIR)organic solar cells(OSCs)and organic photodiodes(OPDs)thanks to their complementary absorption,tunable energy levels,and enhanced stability.However,high-performance NIR photodetectors are still scarce due to the absence of narrow bandgap NFAs.Herein,an asymmetric A-D-π-A type NFA,named ABTPV-S,with a broad optical absorption approaching 1,000 nm is designed and synthesized through integrating alkylthio side chains and a vinyleneπ-bridge.The optimal inverted OPD device exhibits an excellent performance with a photoresponsivity of 0.39 AW-1,a noise current of 2.25×10^(-14)A Hz^(-0.5),a specific detectivity(D*)of 3.43×10^(12)Jones at 840 nm,and linear dynamic range(LDR)of 140 d B.In addition,the rise and fall times for ABTPV-S-based OPDs also reach 1.07 and 0.71μs,respectively.ABTPV-S-based OPDs exhibit a high D*over 1012Jones at 950 nm,which is a competitive result for the self-powered photodiode-type NIR OPDs.These findings highlight the outstanding potential of asymmetric A-D-π-A type NIR NFAs for high-performance OPDs competing with their silicon counterparts.
