In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor depo...In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor deposition method.Photoluminescence measurements indicate the In Ga As nanowires have strong light emission in near-infrared region. For the first time, photodetector based on as-grown In Ga As nanowires was also constructed. It shows good light response over a broad spectral range in infrared region with responsivity of 6.5×10~3 AW^(-1) and external quantum efficiency of 5.04×10~5%. This photodetector may have potential applications in integrated optoelectronic devices and systems.展开更多
High-quality narrow bandgap semiconductors nanowires(NWs)challenge the flexible near-infrared(NIR)photodetectors in next-generation imaging,data communication,environmental monitoring,and bioimaging applications.In th...High-quality narrow bandgap semiconductors nanowires(NWs)challenge the flexible near-infrared(NIR)photodetectors in next-generation imaging,data communication,environmental monitoring,and bioimaging applications.In this work,complementary metal oxide semiconductor-compatible metal of Ag is deposited on glass as the growth catalyst for the surfactantassisted chemical vapor deposition of GaSb NWs.The uniform morphology,balance stoichiometry,high-quality crystallinity,and phase purity of as-prepared NWs are checked by scanning electron microscopy,energy dispersive X-ray spectroscopy,high-resolution transmission electron microscopy,and X-ray diffraction.The electrical properties of as-prepared NWs are studied by constructing back-gated field-effect-transistors,displaying a high I_(on)/I_(off) ratio of 10^(4) and high peak hole mobility of 400 cm^(2)/(V·s).Benefiting from the excellent electrical and mechanical flexibility properties,the as-fabricated NW flexible NIR photodetector exhibits high sensitivity and excellent photoresponse,with responsivity as high as 618 A/W and detectivity as high as 6.7×10^(10) Jones.Furthermore,there is no obvious decline in NIR photodetection behavior,even after parallel and perpendicular folding with 1200 cycles.展开更多
In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaA...In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaAs heterojunction device exhibited obvious photovoltaic behavior to 808 nm illumination,indicating that the near-infrared photodetector can be used as a self-driven device without external power supply.Further device analysis showed that the hybrid heterojunction exhibited a high on/off ratio of 1.16×10^5 measured at 808 nm under zero bias voltage.The responsivity and specific detectivity of photodetector were estimated to be 171.34 mA/W and 2.36×10^11 Jones,respectively.Moreover,the device showed excellent stability and reliable repeatability.After 2 months,the photoelectric characteristics of the near-infrared photodetector hardly degrade in air,attributable to the good stability of the PdSe2.Finally,the PdSe2/GaAs-based heterojunction device can also function as a near-infrared light sensor.展开更多
In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide（β-FeSi2） as the active region for the first time.The optoelectronic characteristics o...In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide（β-FeSi2） as the active region for the first time.The optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room temperature.The results show that the photodetector has a good rectifying character and a good response to near-infrared light.Interface states should be minimized to obtain a lower reverse leakage current.The response spectrum of the β-FeSi2/4H-SiC detector,which consists of a p-type β-FeSi2 absorption layer with a doping concentration of 1×1015cm-3 and a thickness of 2.5 μm,has a peak of 755 mA/W at 1.42 μm.The illumination of the SiC side obtains a higher responsivity than that of the β-FeSi2 side.The results illustrate that the β-FeSi2/4H-SiC heterojunction can be used as a near-infrared photodetector compatible with near-infrared optically-activated SiC-based power switching devices.展开更多
Comprehensive Summary Near infrared light organic photodetectors have attracted tremendous attention due to their tailorable response,ease of processing,compatibility with flexible substrate,room temperature operation...Comprehensive Summary Near infrared light organic photodetectors have attracted tremendous attention due to their tailorable response,ease of processing,compatibility with flexible substrate,room temperature operation and broad applications such as remote sensing,health monitoring,artificial vision,night vision,and so on.Recently,the great improvement obtained on the important figures of merit performances has made organic photodetectors catch up and even surpass those of inorganic photodetectors in some respects.In this review,after a brief illustration of the organic photodetectors'figures of merit performances,we summarize the research progress of panchromatic and narrowband near infrared light organic photodetectors from their working mechanism,strategies to achieve narrowband near infrared light organic photodetectors,to some practical applications.Finally,we discuss the development challenge of the near infrared light organic photodetectors.展开更多
Recently,the rapid development of non-fullerene acceptors(NFAs)has laid the foundation for performance improvements in near-infrared(NIR)organic photodetectors(OPDs).However,reducing the bandgap of NFAs to achieve str...Recently,the rapid development of non-fullerene acceptors(NFAs)has laid the foundation for performance improvements in near-infrared(NIR)organic photodetectors(OPDs).However,reducing the bandgap of NFAs to achieve strong absorption in the shorter-wave region usually leads to increased dark current density(J_(d))and decreased responsivity(R),severely limiting the detectivity(D*)of NIR-OPDs.To date,it remains challenging to manipulate the J_(d) of NIR-OPDs through rational structure engineering of NFAs.Herein,three NIR-NFAs,namely bis(2-decyltetradecyl)4,4′-(2′,7′-di-tert-butylspiro[cyclopenta[2,1-b:3,4-b′]dithiophene-4,9′-fluorene]-2,6-diyl)bis(6-(((Z)-1-(dicyanomethylene)-5,6-difluoro-3-oxo-1,3-dihydro-2H-inden-2-ylidene)methyl)thieno[3,4-b]thiophene-2-carboxylate)(TSIC-4F),bis(2-decyltetradecyl)6,6′-(2′,7′-di-tert-butylspiro[cyclopenta[2,1-b:3,4-b′]dithiophene-4,9′-fluorene]-2,6-diyl)bis(4-(((Z)-1-(dicyanomethylene)-5,6-difluoro-3-oxo-1,3-dihydro-2H-inden-2-ylidene)methyl)thieno[3,4-b]thiophene-2-carboxylate)(STIC-4F),and 2,2′-((2Z,2′Z)-(((2′,7′-di-tert-butylspiro[cyclopenta[2,1-b:3,4-b′]dithiophene-4,9′-fluorene]-2,6-diyl)bis(2,3-bis(5-(2-butyloctyl)thiophen-2-yl)thieno[3,4-b]pyrazine-7,5-diyl))bis(metha-neylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(TPIC-4F),were designed using the thieno[3,4-b]thiophene(TT)and thieno[3,4-b]pyrazine(TPy)derivatives as theπ-bridge.Owing to the intramolecular S-S and S-N interactions,STIC-4F and TPIC-4F exhibited smaller backbone distortions than TSIC-4F.A significantly red-shifted absorption with a peak at 1015 nm was observed in TPIC-4F film,larger than that(ca.960 nm)for TSIC-4F and STIC-4F films.Moreover,OPDs operating in a photovoltaic mode were successfully fabricated,and TPIC-4F-based OPDs achieved the lowest J_(d) of 3.18×10^(-8) A/cm^(2) at-0.1 V.Impressively,although TPIC-4F-based OPDs exhibited the lowest R,higher shot-noise-limited specific detectivity(D_(sh)*)in 1000-1200 nm could be achieved due to its lowest J_(d).This study underscored the effectiveness of optimizing theπ-bridge structure of NFAs to suppress J_(d),ultimately attaining higher D_(sh)*in the NIR region.展开更多
Near-infrared(NIR)organic photodetectors(OPDs)are promising in flexible electronic and imaging sensor applications.However,high-performance NIR-II OPDs with photoresponse wavelength beyond 1000 nm are rare due to the ...Near-infrared(NIR)organic photodetectors(OPDs)are promising in flexible electronic and imaging sensor applications.However,high-performance NIR-II OPDs with photoresponse wavelength beyond 1000 nm are rare due to the lack of narrow bandgap molecular acceptors.In this work,an A-D-A′-D-Atype molecular acceptor with an onset absorption wavelength of 1150 nm was developed.Its narrow bandgap was benefited by the balanced resonance of the boron-nitrogen covalent bond(B–N)and boron-nitrogen coordination bond(B←N)in thienyl-fused 4-difluoro-4-bora-3a,4a-diaza-s-indacene(BODIPY)unit,as well as the strong intramolecular charge transfer(ICT)effect.The molecule showed a strong NIR absorption with an absorption peak at 1019 nm and an optical bandgap as low as 1.07 eV.Using the molecule as an electron acceptor in OPD device fabrication,a wide photoresponse wavelength range of 300 to∼1150 nm was achieved.At bias of−0.1 V,the device showed a low dark current density of 4.59×10^(−8) A cm^(−2) and high responsivity of 0.29 A W^(−1) at 970 nm,achieving a high peak specific detectivity of 2.39×1012 Jones and remaining a high specific detectivity of 1.59×10^(12) Jones at 1064 nm.These results demonstrate a feasible design of ultra-narrow bandgap molecular acceptors based on BODIPY unit induction of highly sensitive NIR-II OPDs.展开更多
The efficient near-infrared light detection of the MoTe2/germanium(Ge)heterojunction has been demonstrated.The fabricated MoTe2/Ge van der Waals heterojunction shows excellent photoresponse performances under the illu...The efficient near-infrared light detection of the MoTe2/germanium(Ge)heterojunction has been demonstrated.The fabricated MoTe2/Ge van der Waals heterojunction shows excellent photoresponse performances under the illumination of a 915 nm laser.The photoresponsivity and specific detectivity can reach to 12,460 A/W and 3.3×10^12 Jones,respectively.And the photoresponse time is 5 ms.However,the MoTe2/Ge heterojunction suffers from a large reverse current at dark due to the low barrier between MoTe2 and Ge.Therefore,to reduce the reverse current,an ultrathin GeO2 layer deposited by ozone oxidation has been introduced to the MoTe2/Ge heterojunction.The reverse current of the MoTe2/GeO2/Ge heterojunction at dark was suppressed from 0.44µA/µm^2 to 0.03 nA/µm^2,being reduced by more than four orders of magnitude.The MoTe2/Ge heterojunction with the GeO2 layer also exhibits good photoresponse performances,with a high responsivity of 15.6 A/W,short response time of 5 ms,and good specific detectivity of 4.86×10^11 Jones.These properties suggest that MoTe2/Ge heterostructure is one of the promising structures for the development of high performance near-infrared photodetectors.展开更多
Flexible narrowband near infrared(NIR)photodetectors(PDs)are urgently in demand in the fastdeveloping era of flexible electronics,due to their crucial roles in various innovative applications.Hence,we designed and syn...Flexible narrowband near infrared(NIR)photodetectors(PDs)are urgently in demand in the fastdeveloping era of flexible electronics,due to their crucial roles in various innovative applications.Hence,we designed and synthesized the core-shell structured NaYF4:Yb^(3+),Er^(3+)@NaYF4:Nd^(3+)upconversion nanoparticles(UCNPs),which can be pumped by the 808 and 980 nm lights.The upconversion luminescence(UCL)are significantly enhanced after being assembled with the opal photonic crystals(OPCs)due to the photonic crystal effect,with 55 and 48 folds of enhancement factors under illuminations of 808 and 980 nm lights,respectively.Based on this hybrid,the flexible narrowband PDs were successfully fabricated on the PET substrate with the structure of OPCs/NaYF4:Yb^(3+),Er^(3+)@Nd^(3+)/MAPbl3,which displays excellent detection performance to double narrowband NIR light(808 and 980 nm)benefiting from the amplified UCL,with responsivity of 8.79 and 7.39 A/W,detectivity of 3.01×10^(11)and2.68×10^(11)cm·Hz^(1/2)/W for 808 and 980 nm lights detection respectively,along with short response time in the range of 120-160 ms.Furthermore,the OPCs/NaYF4:Yb^(3+),Er^(3+)@NaYF4:Nd^(3+)/MAPbI3 double narrowband PDs display low photodetection power threshold(0.05 W/cm2),outstanding flexibility,prominent moisture resistance,and good long-time stability.This work displays a new concept of narrowband NIR PDs,which open a new field for specific NIR light detections.展开更多
To develop high-performance photodetectors(PDs) as near-infrared(NIR) imaging sensors, researchers have either proposed new photoelectric materials, introduced complicated interface-processing steps, or created comple...To develop high-performance photodetectors(PDs) as near-infrared(NIR) imaging sensors, researchers have either proposed new photoelectric materials, introduced complicated interface-processing steps, or created complex optical structures. In this study, we introduce a solution-processed organic material, PEDOT:PSS(PEDOT corresponds to a polymer of 3,4-ethylene dioxythiophene(EDOT), and PSS corresponds to a polystyrene sulfonate), to germanium(Ge) wafers using a convenient spincoating method to improve the photoresponse performance of Ge-based PDs. The Ge wafers and PEDOT:PSS form a heterojunction that reduces the dark current when compared with the Ge Schottky PD(Au/Ge/Ag PD). The experimental results show that the Au/PEDOT:PSS/Ge/Ag heterojunction PD with a bias voltage of 0 V at 1550 nm exhibits a responsivity(R) of 0.26 A/W,a detectivity(D*) of 6.5×1011 Jones, a linear dynamic range(LDR) of 124 d B, and a bandwidth(-3 dB) of 10 k Hz. This implies that the performance of the PD is comparable to that of previously reported Ge-based PDs. Subsequently, a biomedical imaging application of the PD is successfully demonstrated through foreign-body detection. Therefore, it is expected that the selfpowered Au/PEDOT:PSS/Ge/Ag PD will be highly suitable for NIR imaging.展开更多
Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. T...Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. The photocurrent for the device with 5 μm interdigital spacing is five orders of magnitude higher than the dark current, and the room temperature detectivity is on the order of 2.4 × 1012cm Hz1∕2W-1at 5 V bias. Furthermore,the spectral response of this device possesses strong dependence on the polarization of incident light showing potential plasmonic effects with only microscale dimensions. These experimental data were analyzed using optical simulation to confirm the response of the devices.展开更多
Narrowband photodetectors as specific spectral sensing pixels have drawn intense attention in multispectral detection due to their distinct characteristic of filter-free spectrum discrimination,in which the emerging h...Narrowband photodetectors as specific spectral sensing pixels have drawn intense attention in multispectral detection due to their distinct characteristic of filter-free spectrum discrimination,in which the emerging halide lead perovskites witness a booming development in their performance and wavelength-selectivity from blue to near-infrared light.However,the challenge in integrating perovskite narrowband photodetectors on one chip imposes an impediment on practical application.In this work,the combination of laser-direct-writing and ion exchange is proposed as an efficient way to fabricate high-definition colorful sensing array with perovskite narrowband photodetector unit as pixel.Under laser irradiation,the photolysis of halocarbon solvent(CHCl_(3),CH_(3)CH_(2)I,etc)releases the halide ions,which brings the ion exchange and gives rise to slow-varying bandgap in single perovskite photoactive film.This ion exchange can be controlled via laser irradiation time and focus point,thus enabling precisely engineerable bandgap.By optimizing the process,it is successfully applied to develop patterned perovskite narrow blue and green photodetectors array with a high-definition of~53 ppi.We believe this result will make a great step forward to integrate multifunctional perovskite devices on one chip,which will pave the way for perovskite optoelectronic device to the commercial application.展开更多
Tunneling heterostructures are emerging as a versatile architecture for photodetection due to their advanced optical sensitivity,tailorable detection band,and wellbalanced photoelectric performances.However,the existi...Tunneling heterostructures are emerging as a versatile architecture for photodetection due to their advanced optical sensitivity,tailorable detection band,and wellbalanced photoelectric performances.However,the existing tunneling heterostructures are mainly operated in the visible wavelengths and have been rarely investigated for the nearinfrared detection.Herein,we report the design and realization of a novel broken-gap tunneling heterostructure by combining WSe2 and Bi2Se3,which is able to realize the simultaneous visible and near-infrared detection because of the complementary bandgaps of WSe2 and Bi2Se3(1.46 and 0.3 e V respectively).Thanks to the realigned band structure,the heterostructure shows an ultralow dark current below picoampere and a high tunneling-dominated photocurrent.The photodetector based on our tunneling heterostructure exhibits a superior specific detectivity of 7.9×1012Jones for a visible incident of 532 nm and 2.2×1010Jones for a 1456 nm nearinfrared illumination.Our study demonstrates a new band structure engineering avenue for the construction of van der Waals tunneling heterostructures for high-performance wide band photodetection.展开更多
Lead telluride(PbTe)is one of the reliable candidates for infrared(IR)optoelectronics with optimum band-gap as well as excellent photoelectric properties.Great interests had been paid on the growth and device applicat...Lead telluride(PbTe)is one of the reliable candidates for infrared(IR)optoelectronics with optimum band-gap as well as excellent photoelectric properties.Great interests had been paid on the growth and device applications with PbTe for the development of high-performance IR photodetectors especially those working in the near-infrared regime.Although a great deal of effort had been made to prepare PbTe nanostructures for miniaturized detectors,it is difficult to synthesize high-quality two-dimensional(2D)PbTe crystals due to its rock-salt non-layered structure.Herein,a facile strategy for controllable synthesis of ultrathin crystalline PbTe nanosheets by van der Waals epitaxy is reported.With an optimized growth temperature,which determines the morphology transit from triangular pyramid islands to regular square 2D planars,PbTe nanosheets in lateral size of tens of microns with thickness down to~7 nm are achieved.Meanwhile,ultrasensitive near-infrared detectors(NIRDs)based on the as-grown 2D PbTe nanosheets have been demonstrated with an ultrahigh responsivity exceeding 3,847 A/W at the wavelength of 1,550 nm under room temperature.Our approach demonstrates that 2D PbTe nanosheets have great latent capacity of developing high-performance miniaturized IR optoelectronic devices.展开更多
Cd_(3)As_(2)nanowires(NWs)have great potential in the near-infrared(NIR)photodetection field due to their excellent optoelectronic properties as a typical Dirac semimetal.However,the existence of surface oxidization l...Cd_(3)As_(2)nanowires(NWs)have great potential in the near-infrared(NIR)photodetection field due to their excellent optoelectronic properties as a typical Dirac semimetal.However,the existence of surface oxidization limits their photoresponse performance for practical applications.Here,we modified the surface of Cd_(3)As_(2)NWs with sulfur to prevent surface oxidizing and optimize the bandgap structure to improve the photoresponse performance.The S-modified Cd_(3)As_(2)samples existed as core/shell Cd_(3)As_(2)/CdS NWs and the corresponding single NW device showed a responsivity of 0.95 A/W in the NIR band at a 0 V bias,which is three orders of magnitude higher than that of an unmodified NW.This study provides an efficient and universally applicable way to prevent semimetals nanostructures from oxidizing and promote their optoelectronic properties.展开更多
We demonstrate that the near-infrared （NIR） absorptivity of semiconducfing single-walled carbon nanotubes （s-SWCNTs） can be harnessed in blended heterojunctions with the fullerene derivative [6,6]-phenyl-C61-butyr...We demonstrate that the near-infrared （NIR） absorptivity of semiconducfing single-walled carbon nanotubes （s-SWCNTs） can be harnessed in blended heterojunctions with the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester （PCBM）. Photogenerated charge separation is efficiently driven by the ultrahigh interracial area of the blends and the favorable energy offsets between the two materials. NIR-sensitive photovoltaic and photodetector devices utilizing the stack （indium tin oxide/ca. 10 nm s-SWCNT：PCBM/100 nm CJ10 nm 2,9- dimethyl-4,7-diphenyl-],10-phenanthroline （BCP）/Ag） were fabricated with NIR power conversion efficiencies 〉1.3% and peak, zero bias external quantum efficiency of 18% at λ = 1205 nm.展开更多
基金the NSF of China(Nos.61574054,61505051,11374092,11204073,61474040,and51302077)the National Basic Research Program of China(No.2012CB932703)+2 种基金the Hunan province science and technology plan(No.2014FJ2001,2014GK3015,and 2014TT1004)the Hunan Provincial Natural Science Foundation of China(No.2015JJ3049)the Aid program for Science and Technology Innovative Research Team in Higher Educational Institutions of Hunan Province
文摘In Ga As is an important bandgap-variable ternary semiconductor which has wide applications in electronics and optoelectronics. In this work, single-crystal In Ga As nanowires were synthesized by a chemical vapor deposition method.Photoluminescence measurements indicate the In Ga As nanowires have strong light emission in near-infrared region. For the first time, photodetector based on as-grown In Ga As nanowires was also constructed. It shows good light response over a broad spectral range in infrared region with responsivity of 6.5×10~3 AW^(-1) and external quantum efficiency of 5.04×10~5%. This photodetector may have potential applications in integrated optoelectronic devices and systems.
基金the National Key R&D Program of China (No.2017YFA0305500)National Natural Science Foundation of China (Nos.61904096,11504207)+3 种基金Taishan Scholars Program of Shandong Province (No.tsqn201812006)Shandong Univ ersity Youth Innovation Supporting Program (No.2019-KJN020)Shandong University Multidisciplinary Research and Innovation Team of Young Scholars (No.2020QNQT015)“Outstanding youth scholar and Qilu young scholar” programs of Shandong University.
文摘High-quality narrow bandgap semiconductors nanowires(NWs)challenge the flexible near-infrared(NIR)photodetectors in next-generation imaging,data communication,environmental monitoring,and bioimaging applications.In this work,complementary metal oxide semiconductor-compatible metal of Ag is deposited on glass as the growth catalyst for the surfactantassisted chemical vapor deposition of GaSb NWs.The uniform morphology,balance stoichiometry,high-quality crystallinity,and phase purity of as-prepared NWs are checked by scanning electron microscopy,energy dispersive X-ray spectroscopy,high-resolution transmission electron microscopy,and X-ray diffraction.The electrical properties of as-prepared NWs are studied by constructing back-gated field-effect-transistors,displaying a high I_(on)/I_(off) ratio of 10^(4) and high peak hole mobility of 400 cm^(2)/(V·s).Benefiting from the excellent electrical and mechanical flexibility properties,the as-fabricated NW flexible NIR photodetector exhibits high sensitivity and excellent photoresponse,with responsivity as high as 618 A/W and detectivity as high as 6.7×10^(10) Jones.Furthermore,there is no obvious decline in NIR photodetection behavior,even after parallel and perpendicular folding with 1200 cycles.
基金supported by the National Natural Science Foundation of China(No.61575059,No.61675062,No.21501038)the Fundamental Research Funds for the Central Universities(No.JZ2018HGPB0275,No.JZ2018HGTA0220,and No.JZ2018HGXC0001).
文摘In this study,we have developed a high-sensitivity,near-infrared photodetector based on PdSe2/GaAs heterojunction,which was made by transferring a multilayered PdSe2 film onto a planar GaAs.The as-fabricated PdSe2/GaAs heterojunction device exhibited obvious photovoltaic behavior to 808 nm illumination,indicating that the near-infrared photodetector can be used as a self-driven device without external power supply.Further device analysis showed that the hybrid heterojunction exhibited a high on/off ratio of 1.16×10^5 measured at 808 nm under zero bias voltage.The responsivity and specific detectivity of photodetector were estimated to be 171.34 mA/W and 2.36×10^11 Jones,respectively.Moreover,the device showed excellent stability and reliable repeatability.After 2 months,the photoelectric characteristics of the near-infrared photodetector hardly degrade in air,attributable to the good stability of the PdSe2.Finally,the PdSe2/GaAs-based heterojunction device can also function as a near-infrared light sensor.
基金Project supported by the National Natural Science Foundation of China (Grant Nos. 60876050 and 51177134)
文摘In this paper,we propose a near-infrared p-type β-FeSi2/n-type 4H-SiC heterojunction photodetector with semiconducting silicide（β-FeSi2） as the active region for the first time.The optoelectronic characteristics of the photodetector are simulated using a commercial simulator at room temperature.The results show that the photodetector has a good rectifying character and a good response to near-infrared light.Interface states should be minimized to obtain a lower reverse leakage current.The response spectrum of the β-FeSi2/4H-SiC detector,which consists of a p-type β-FeSi2 absorption layer with a doping concentration of 1×1015cm-3 and a thickness of 2.5 μm,has a peak of 755 mA/W at 1.42 μm.The illumination of the SiC side obtains a higher responsivity than that of the β-FeSi2 side.The results illustrate that the β-FeSi2/4H-SiC heterojunction can be used as a near-infrared photodetector compatible with near-infrared optically-activated SiC-based power switching devices.
基金the financial support from the National Natural Science Foundation of China(Grant Nos.21975059,22135001,21721002)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB36000000)+1 种基金International Partnership Program of the Chinese Academy of Sciences(No.121D11KYSB20190080)Open project of the State Key Laboratory of Electronic Thin Films and Integrated Devices,University of Electronic Science and Technology of China(No.KFJ202101).
文摘Comprehensive Summary Near infrared light organic photodetectors have attracted tremendous attention due to their tailorable response,ease of processing,compatibility with flexible substrate,room temperature operation and broad applications such as remote sensing,health monitoring,artificial vision,night vision,and so on.Recently,the great improvement obtained on the important figures of merit performances has made organic photodetectors catch up and even surpass those of inorganic photodetectors in some respects.In this review,after a brief illustration of the organic photodetectors'figures of merit performances,we summarize the research progress of panchromatic and narrowband near infrared light organic photodetectors from their working mechanism,strategies to achieve narrowband near infrared light organic photodetectors,to some practical applications.Finally,we discuss the development challenge of the near infrared light organic photodetectors.
基金supported by the National Natural Science Foundation of China(Nos.U21A6002,51933003,52203355)the Basic and Applied Basic Research Foundation of Guangdong Province,China(Nos.2019B030302007,2023A1515012293)the Guangzhou Science and Technology Plan Project,China(No.2023A04J0970).
文摘Recently,the rapid development of non-fullerene acceptors(NFAs)has laid the foundation for performance improvements in near-infrared(NIR)organic photodetectors(OPDs).However,reducing the bandgap of NFAs to achieve strong absorption in the shorter-wave region usually leads to increased dark current density(J_(d))and decreased responsivity(R),severely limiting the detectivity(D*)of NIR-OPDs.To date,it remains challenging to manipulate the J_(d) of NIR-OPDs through rational structure engineering of NFAs.Herein,three NIR-NFAs,namely bis(2-decyltetradecyl)4,4′-(2′,7′-di-tert-butylspiro[cyclopenta[2,1-b:3,4-b′]dithiophene-4,9′-fluorene]-2,6-diyl)bis(6-(((Z)-1-(dicyanomethylene)-5,6-difluoro-3-oxo-1,3-dihydro-2H-inden-2-ylidene)methyl)thieno[3,4-b]thiophene-2-carboxylate)(TSIC-4F),bis(2-decyltetradecyl)6,6′-(2′,7′-di-tert-butylspiro[cyclopenta[2,1-b:3,4-b′]dithiophene-4,9′-fluorene]-2,6-diyl)bis(4-(((Z)-1-(dicyanomethylene)-5,6-difluoro-3-oxo-1,3-dihydro-2H-inden-2-ylidene)methyl)thieno[3,4-b]thiophene-2-carboxylate)(STIC-4F),and 2,2′-((2Z,2′Z)-(((2′,7′-di-tert-butylspiro[cyclopenta[2,1-b:3,4-b′]dithiophene-4,9′-fluorene]-2,6-diyl)bis(2,3-bis(5-(2-butyloctyl)thiophen-2-yl)thieno[3,4-b]pyrazine-7,5-diyl))bis(metha-neylylidene))bis(5,6-difluoro-3-oxo-2,3-dihydro-1H-indene-2,1-diylidene))dimalononitrile(TPIC-4F),were designed using the thieno[3,4-b]thiophene(TT)and thieno[3,4-b]pyrazine(TPy)derivatives as theπ-bridge.Owing to the intramolecular S-S and S-N interactions,STIC-4F and TPIC-4F exhibited smaller backbone distortions than TSIC-4F.A significantly red-shifted absorption with a peak at 1015 nm was observed in TPIC-4F film,larger than that(ca.960 nm)for TSIC-4F and STIC-4F films.Moreover,OPDs operating in a photovoltaic mode were successfully fabricated,and TPIC-4F-based OPDs achieved the lowest J_(d) of 3.18×10^(-8) A/cm^(2) at-0.1 V.Impressively,although TPIC-4F-based OPDs exhibited the lowest R,higher shot-noise-limited specific detectivity(D_(sh)*)in 1000-1200 nm could be achieved due to its lowest J_(d).This study underscored the effectiveness of optimizing theπ-bridge structure of NFAs to suppress J_(d),ultimately attaining higher D_(sh)*in the NIR region.
基金the financial support from the National Natural Science Foundation of China(grant no.22135007)the Natural Science Foundation of Jilin Province,China(grant no.20230101122JC).
文摘Near-infrared(NIR)organic photodetectors(OPDs)are promising in flexible electronic and imaging sensor applications.However,high-performance NIR-II OPDs with photoresponse wavelength beyond 1000 nm are rare due to the lack of narrow bandgap molecular acceptors.In this work,an A-D-A′-D-Atype molecular acceptor with an onset absorption wavelength of 1150 nm was developed.Its narrow bandgap was benefited by the balanced resonance of the boron-nitrogen covalent bond(B–N)and boron-nitrogen coordination bond(B←N)in thienyl-fused 4-difluoro-4-bora-3a,4a-diaza-s-indacene(BODIPY)unit,as well as the strong intramolecular charge transfer(ICT)effect.The molecule showed a strong NIR absorption with an absorption peak at 1019 nm and an optical bandgap as low as 1.07 eV.Using the molecule as an electron acceptor in OPD device fabrication,a wide photoresponse wavelength range of 300 to∼1150 nm was achieved.At bias of−0.1 V,the device showed a low dark current density of 4.59×10^(−8) A cm^(−2) and high responsivity of 0.29 A W^(−1) at 970 nm,achieving a high peak specific detectivity of 2.39×1012 Jones and remaining a high specific detectivity of 1.59×10^(12) Jones at 1064 nm.These results demonstrate a feasible design of ultra-narrow bandgap molecular acceptors based on BODIPY unit induction of highly sensitive NIR-II OPDs.
基金supported by the National Key Research and Development Program of China(Nos.2016YFA0200400 and 2016YFA0302300)the National Science and Technology Major Project of China(No.2016ZX02301001).
文摘The efficient near-infrared light detection of the MoTe2/germanium(Ge)heterojunction has been demonstrated.The fabricated MoTe2/Ge van der Waals heterojunction shows excellent photoresponse performances under the illumination of a 915 nm laser.The photoresponsivity and specific detectivity can reach to 12,460 A/W and 3.3×10^12 Jones,respectively.And the photoresponse time is 5 ms.However,the MoTe2/Ge heterojunction suffers from a large reverse current at dark due to the low barrier between MoTe2 and Ge.Therefore,to reduce the reverse current,an ultrathin GeO2 layer deposited by ozone oxidation has been introduced to the MoTe2/Ge heterojunction.The reverse current of the MoTe2/GeO2/Ge heterojunction at dark was suppressed from 0.44µA/µm^2 to 0.03 nA/µm^2,being reduced by more than four orders of magnitude.The MoTe2/Ge heterojunction with the GeO2 layer also exhibits good photoresponse performances,with a high responsivity of 15.6 A/W,short response time of 5 ms,and good specific detectivity of 4.86×10^11 Jones.These properties suggest that MoTe2/Ge heterostructure is one of the promising structures for the development of high performance near-infrared photodetectors.
基金Project supported by the National Natural Science Foundation of China(11974143,11874181,61822506,U1801253,11904124)the Special Project of the Province-University Co-constructing Program of Jilin Province(SXGJXX2017-3)。
文摘Flexible narrowband near infrared(NIR)photodetectors(PDs)are urgently in demand in the fastdeveloping era of flexible electronics,due to their crucial roles in various innovative applications.Hence,we designed and synthesized the core-shell structured NaYF4:Yb^(3+),Er^(3+)@NaYF4:Nd^(3+)upconversion nanoparticles(UCNPs),which can be pumped by the 808 and 980 nm lights.The upconversion luminescence(UCL)are significantly enhanced after being assembled with the opal photonic crystals(OPCs)due to the photonic crystal effect,with 55 and 48 folds of enhancement factors under illuminations of 808 and 980 nm lights,respectively.Based on this hybrid,the flexible narrowband PDs were successfully fabricated on the PET substrate with the structure of OPCs/NaYF4:Yb^(3+),Er^(3+)@Nd^(3+)/MAPbl3,which displays excellent detection performance to double narrowband NIR light(808 and 980 nm)benefiting from the amplified UCL,with responsivity of 8.79 and 7.39 A/W,detectivity of 3.01×10^(11)and2.68×10^(11)cm·Hz^(1/2)/W for 808 and 980 nm lights detection respectively,along with short response time in the range of 120-160 ms.Furthermore,the OPCs/NaYF4:Yb^(3+),Er^(3+)@NaYF4:Nd^(3+)/MAPbI3 double narrowband PDs display low photodetection power threshold(0.05 W/cm2),outstanding flexibility,prominent moisture resistance,and good long-time stability.This work displays a new concept of narrowband NIR PDs,which open a new field for specific NIR light detections.
基金supported by the National Natural Science Foundation of China(Grant No.51772135)the China Postdoctoral Science Foundation(Grant No.2019M663363)。
文摘To develop high-performance photodetectors(PDs) as near-infrared(NIR) imaging sensors, researchers have either proposed new photoelectric materials, introduced complicated interface-processing steps, or created complex optical structures. In this study, we introduce a solution-processed organic material, PEDOT:PSS(PEDOT corresponds to a polymer of 3,4-ethylene dioxythiophene(EDOT), and PSS corresponds to a polystyrene sulfonate), to germanium(Ge) wafers using a convenient spincoating method to improve the photoresponse performance of Ge-based PDs. The Ge wafers and PEDOT:PSS form a heterojunction that reduces the dark current when compared with the Ge Schottky PD(Au/Ge/Ag PD). The experimental results show that the Au/PEDOT:PSS/Ge/Ag heterojunction PD with a bias voltage of 0 V at 1550 nm exhibits a responsivity(R) of 0.26 A/W,a detectivity(D*) of 6.5×1011 Jones, a linear dynamic range(LDR) of 124 d B, and a bandwidth(-3 dB) of 10 k Hz. This implies that the performance of the PD is comparable to that of previously reported Ge-based PDs. Subsequently, a biomedical imaging application of the PD is successfully demonstrated through foreign-body detection. Therefore, it is expected that the selfpowered Au/PEDOT:PSS/Ge/Ag PD will be highly suitable for NIR imaging.
基金supported by the Air Force Office of Scientific Research (Grant No. FA9550-10-1-0136)NASA (Grant No. 242026-1BBX11AQ36A)+1 种基金supported by a University of Arkansas Honors College Undergraduate Research grantthe Microelectronics–Photonics program at the University of Arkansas for the COMSOL license
文摘Metal-semiconductor-metal photodetectors on semi-insulating Ga As with interdigital electrodes showed significant enhancement in the spectral response in the near-infrared region as the electrode spacing is reduced. The photocurrent for the device with 5 μm interdigital spacing is five orders of magnitude higher than the dark current, and the room temperature detectivity is on the order of 2.4 × 1012cm Hz1∕2W-1at 5 V bias. Furthermore,the spectral response of this device possesses strong dependence on the polarization of incident light showing potential plasmonic effects with only microscale dimensions. These experimental data were analyzed using optical simulation to confirm the response of the devices.
基金supported by the National Natural Science Foundation of China(No.52172146)Natural Science Foundation of Jiangsu Province(Nos.BK20190443 and BK20200071)+7 种基金Shuangchuang Talent of Jiangsu Province(No.JSSCRC2021506)Young Elite Scientists Sponsorship Program by Jiangsu CAST(No.JS19TJGC132574)2019 Overseas Students'Science and Technology Innovation Project Selection Funding of Nanjing,Fundamental Research Funds for the Central Universities(Nos.30919011298,30919011299 and 30919012107)National Key R&D Program of China(No.2017YFA0305500)the National Natural Science Foundation of China(Nos.61725402,11604152,and 51672132)the National“ten thousand talents plan”leading talents(No.W03020394)the Six top talent innovation teams of Jiangsu Province(No.TD-XCL-004)Y.D.and Z.H.conducted all the experiments.Y.D.and X.X.wrote the manuscript.Y.Z.and H.Z.supervised this project.
文摘Narrowband photodetectors as specific spectral sensing pixels have drawn intense attention in multispectral detection due to their distinct characteristic of filter-free spectrum discrimination,in which the emerging halide lead perovskites witness a booming development in their performance and wavelength-selectivity from blue to near-infrared light.However,the challenge in integrating perovskite narrowband photodetectors on one chip imposes an impediment on practical application.In this work,the combination of laser-direct-writing and ion exchange is proposed as an efficient way to fabricate high-definition colorful sensing array with perovskite narrowband photodetector unit as pixel.Under laser irradiation,the photolysis of halocarbon solvent(CHCl_(3),CH_(3)CH_(2)I,etc)releases the halide ions,which brings the ion exchange and gives rise to slow-varying bandgap in single perovskite photoactive film.This ion exchange can be controlled via laser irradiation time and focus point,thus enabling precisely engineerable bandgap.By optimizing the process,it is successfully applied to develop patterned perovskite narrow blue and green photodetectors array with a high-definition of~53 ppi.We believe this result will make a great step forward to integrate multifunctional perovskite devices on one chip,which will pave the way for perovskite optoelectronic device to the commercial application.
基金supported by the National Nature Science Foundation of China(21825103 and 51727809)Hubei Provincial Natural Science Foundation of China(2019CFA002)the Fundamental Research Funds for the Central Universities(2019kfyXMBZ018)。
文摘Tunneling heterostructures are emerging as a versatile architecture for photodetection due to their advanced optical sensitivity,tailorable detection band,and wellbalanced photoelectric performances.However,the existing tunneling heterostructures are mainly operated in the visible wavelengths and have been rarely investigated for the nearinfrared detection.Herein,we report the design and realization of a novel broken-gap tunneling heterostructure by combining WSe2 and Bi2Se3,which is able to realize the simultaneous visible and near-infrared detection because of the complementary bandgaps of WSe2 and Bi2Se3(1.46 and 0.3 e V respectively).Thanks to the realigned band structure,the heterostructure shows an ultralow dark current below picoampere and a high tunneling-dominated photocurrent.The photodetector based on our tunneling heterostructure exhibits a superior specific detectivity of 7.9×1012Jones for a visible incident of 532 nm and 2.2×1010Jones for a 1456 nm nearinfrared illumination.Our study demonstrates a new band structure engineering avenue for the construction of van der Waals tunneling heterostructures for high-performance wide band photodetection.
基金the National Natural Science Foundation of China(Nos.61875223,61922082 and 61927813)the Natural Science Foundation of Hainan Province(No.117111)。
文摘Lead telluride(PbTe)is one of the reliable candidates for infrared(IR)optoelectronics with optimum band-gap as well as excellent photoelectric properties.Great interests had been paid on the growth and device applications with PbTe for the development of high-performance IR photodetectors especially those working in the near-infrared regime.Although a great deal of effort had been made to prepare PbTe nanostructures for miniaturized detectors,it is difficult to synthesize high-quality two-dimensional(2D)PbTe crystals due to its rock-salt non-layered structure.Herein,a facile strategy for controllable synthesis of ultrathin crystalline PbTe nanosheets by van der Waals epitaxy is reported.With an optimized growth temperature,which determines the morphology transit from triangular pyramid islands to regular square 2D planars,PbTe nanosheets in lateral size of tens of microns with thickness down to~7 nm are achieved.Meanwhile,ultrasensitive near-infrared detectors(NIRDs)based on the as-grown 2D PbTe nanosheets have been demonstrated with an ultrahigh responsivity exceeding 3,847 A/W at the wavelength of 1,550 nm under room temperature.Our approach demonstrates that 2D PbTe nanosheets have great latent capacity of developing high-performance miniaturized IR optoelectronic devices.
基金This work was supported by the National Natural Science Foundation of China(Nos.61874111,61625404,61888102,and 62022079)the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2020115).
文摘Cd_(3)As_(2)nanowires(NWs)have great potential in the near-infrared(NIR)photodetection field due to their excellent optoelectronic properties as a typical Dirac semimetal.However,the existence of surface oxidization limits their photoresponse performance for practical applications.Here,we modified the surface of Cd_(3)As_(2)NWs with sulfur to prevent surface oxidizing and optimize the bandgap structure to improve the photoresponse performance.The S-modified Cd_(3)As_(2)samples existed as core/shell Cd_(3)As_(2)/CdS NWs and the corresponding single NW device showed a responsivity of 0.95 A/W in the NIR band at a 0 V bias,which is three orders of magnitude higher than that of an unmodified NW.This study provides an efficient and universally applicable way to prevent semimetals nanostructures from oxidizing and promote their optoelectronic properties.
基金Acknowledgements The authors acknowledge the assistance of Frederick C. Prehn in sample preparation. This work was supported by the National Science Foundation （Grant No. DMR- 0905861）.
文摘We demonstrate that the near-infrared （NIR） absorptivity of semiconducfing single-walled carbon nanotubes （s-SWCNTs） can be harnessed in blended heterojunctions with the fullerene derivative [6,6]-phenyl-C61-butyric acid methyl ester （PCBM）. Photogenerated charge separation is efficiently driven by the ultrahigh interracial area of the blends and the favorable energy offsets between the two materials. NIR-sensitive photovoltaic and photodetector devices utilizing the stack （indium tin oxide/ca. 10 nm s-SWCNT：PCBM/100 nm CJ10 nm 2,9- dimethyl-4,7-diphenyl-],10-phenanthroline （BCP）/Ag） were fabricated with NIR power conversion efficiencies 〉1.3% and peak, zero bias external quantum efficiency of 18% at λ = 1205 nm.
