High-performance and tensile-strained germanium （Ge） p-i-n photodetector is demonstrated on Si substrate. The epi- taxial Ge layers were prepared in an ultrahigh vacuum chemical vapor deposition （UHV-CVD） system u...High-performance and tensile-strained germanium （Ge） p-i-n photodetector is demonstrated on Si substrate. The epi- taxial Ge layers were prepared in an ultrahigh vacuum chemical vapor deposition （UHV-CVD） system using low tem- perature Ge buffer technique. The devices were fabricated by in situ doping and using Si as passivation layer between Ge and metal, which can improve the ohmic contact and realize the high doping. The results show that the dark current of the photodetector with diameter of 24 lain is about 2.5 × 10.7 μA at the bias voltage of-1 V, and the optical responsivity is 0.1 A/W at wavelength of 1.55 μm. The 3 dB bandwidth （BW） of 4 GHz is obtained for the photodetector with diameter of 24 μm at reverse bias voltage of 1 V. The long diffusion time of minority carrier in n-type Ge and the large contact resistance in metal/Ge contacts both affect the performance of Ge photodetectors.展开更多
Flexible and broadband photodetectors have drawn extensive attention due to their potential application in foldable displays, optical communications, environmental monitoring, etc. In this work, a flexible photodetect...Flexible and broadband photodetectors have drawn extensive attention due to their potential application in foldable displays, optical communications, environmental monitoring, etc. In this work, a flexible photodetector based on the crystalline PbS quantum dots(QDs)/ZnO nanoparticles(NPs) heterostructure was proposed. The photodetector exhibits a broadband response from ultraviolet-visible(UV-Vis)to near infrared detector(NIR) range with a remarkable current on/off ratio of 7.08×10^3under 375 nm light illumination.Compared with pure ZnO NPs, the heterostructure photodetector shows the three orders of magnitude higher responsivity in Vis and NIR range, and maintains its performance in the UV range simultaneously. The photodetector demonstrates a high responsivity and detectivity of4.54 A W-1and 3.98×10^12Jones. In addition, the flexible photodetectors exhibit excellent durability and stability even after hundreds of times bending. This work paves a promising way for constructing next-generation high-performance flexible and broadband optoelectronic devices.展开更多
An ultraviolet （UV）-visible tunable photodetec- tor based on ZnO nanorod arrays （NAs）/perovskite hetero- junction solar cell structures is presented, in which the ZnO NAs are prepared using the hydrothermal method...An ultraviolet （UV）-visible tunable photodetec- tor based on ZnO nanorod arrays （NAs）/perovskite hetero- junction solar cell structures is presented, in which the ZnO NAs are prepared using the hydrothermal method and an- nealed in different atmospheres. Based on solar cell structure perovskite photodetectors, it exhibited highly repeatable and stable photoelectric response characteristics. In addition, the devices with ZnO NAs annealed in a vacuum showed a high responsivity of about 1014 cm Hz1/2 W-1 in the visible region, whereas the devices with ZnO NAs annealed in air exhib- Red good detectivity in the UV region, especially at around 350 nm. Furthermore, when the annealing atmosphere of the ZnO nanorods was changed from vacuum to air, the domi- nant detection region of the photodetectors was altered from the visible to the ultraviolet region. These results enable po- tential applications of the ZnO NAs/perovskite photodetec- tors in ultraviolet and visible regions.展开更多
A high performance heterojunction organic ultraviolet photodetector based on NPB and Bphen has been fabricated. A trans- parent conducting polymer PEDOT：PSS coated quartz substrate instead of ITO coated glass substra...A high performance heterojunction organic ultraviolet photodetector based on NPB and Bphen has been fabricated. A trans- parent conducting polymer PEDOT：PSS coated quartz substrate instead of ITO coated glass substrate as anode is propitious to detect shorter wavelength ultraviolet light. As a result, the device shows a low dark current density, a high responsivity of 502 mA/W and a detectivity of 2.67x1012 cm Hz1/Zfw which is illuminated by a 220 nm ultraviolet light with an intensity of 1.6 mW/cm2. Moreover, the performance of the PEDOT：PSS transparent electrode device is better than the semi-transparent A1 electrode device electrode because of the higher transmittance and electrode properties.展开更多
As a lead-free perovskite,CsBi3I10 has attracted significant attention because of its high thermal tolerance and long electron diffusion length.Solution-processed high-performance CsBi3I10 perovskite devices,however,a...As a lead-free perovskite,CsBi3I10 has attracted significant attention because of its high thermal tolerance and long electron diffusion length.Solution-processed high-performance CsBi3I10 perovskite devices,however,are hindered by the formation of a two-dimensional structure,which results in an extremely high surface roughness and many pinholes.In this paper,we reported a space-confined growth(SCG)method using a single-layer polystyrene(PS)sphere template to obtain high-smoothness,high-crystallinity,and dense CsBi3I10 perovskite films.Compared with traditionally spin-coated CsBi3I10 photodetectors(PDs),the metal-semiconductor-metal PDs made by SCG showed a higher photocurrent,a lower dark current,and a bigger on/off ratio.In addition,the photocurrent of our unencapsulated CsBi3I10 perovskite PDs was not attenuated under long-time illumination.In addition,when the device was stored in air for 30 d,its performance also showed no degradation,demonstrating ultra-high stability.Furthermore,the synthesis was free of antisolvents,such as chlorobenzene and toluene,which is beneficial for the environmentally friendly assembly of the devices.Our strategy opens up a new way to prepare high-quality lead-free perovskite,which may be useful for applications in light-emitting diodes and solar cells.展开更多
Linearly bonded triiodide chains with fairly small distance between the adjacent iodine ions feature a facile electron transfer and highly anisotropic properties.Here,we demonstrate a novel strategy towards a new one-...Linearly bonded triiodide chains with fairly small distance between the adjacent iodine ions feature a facile electron transfer and highly anisotropic properties.Here,we demonstrate a novel strategy towards a new one-dimensional linear triiodide DMEDA·I6,using chain-type N,N'-dimethylethanediamine(DMEDA)cation to coordinate triiodine ions.This triiodide has the shortest distance between adjacent I3^- and good linearity.An estimated electronic band gap of1.36 e V indicates its semiconducting properties.100 fold differences both in polarization-sensitive absorption and effective mass were achieved by simulation,with directions parallel and perpendicular to the a-axis of DMEDA·I6.The DMEDA·I6 single crystal-based photodetectors show a good switching characteristic and a distinct polarization-sensitive photoresponse with linear dichroic photodetection ratio of about 1.9.Strongly anisotropic features and semiconducting properties of DMEDA·I6 make this triiodide system an interesting candidate for polarization related applications.展开更多
A simple self-catalyzed chemical vapor deposition process was conducted to synthesize single-crystalline GaSb nanowires,where Ga droplets were utilized as the catalysts.The as-grown GaSb nanowires exhibited typical p-...A simple self-catalyzed chemical vapor deposition process was conducted to synthesize single-crystalline GaSb nanowires,where Ga droplets were utilized as the catalysts.The as-grown GaSb nanowires exhibited typical p-type semiconductor behavior with the calculated hole mobility of about 0.042 cm^2 V^-1 s^-1.The photoresponse properties of the GaSb nanowires were studied by fabricating nanowire photodetectors on both rigid and flexible substrates.The results revealed that the photodetectors exhibited broad spectral response ranging from ultraviolet,visible,to near-infrared region.For the device on rigid substrate,the corresponding responsivity and the detectivity were calculated to be 3.86×10^3 A W-1 and 3.15×10^13 Jones for 500 nm light,and 7.22×10^2 A W-1 and 5.90×10^12 Jones for 808 nm light,respectively,which were the highest value compared with those of other reported Ga1-xInxAsySb1-y structure nanowires.Besides,the flexible photodetectors not only maintained the comparable good photoresponse properties as the rigid one,but also possessed excellent mechanical flexibility and stability.This study could facilitate the understanding on the fundamental characteristics of self-catalyzed grown GaSb nanowires and the design of functional nano-optoelectronic devices based on GaSb nanowires.展开更多
基金supported by the National Natural Science Foundation of China(Nos.61474094 and 61176092)
文摘High-performance and tensile-strained germanium （Ge） p-i-n photodetector is demonstrated on Si substrate. The epi- taxial Ge layers were prepared in an ultrahigh vacuum chemical vapor deposition （UHV-CVD） system using low tem- perature Ge buffer technique. The devices were fabricated by in situ doping and using Si as passivation layer between Ge and metal, which can improve the ohmic contact and realize the high doping. The results show that the dark current of the photodetector with diameter of 24 lain is about 2.5 × 10.7 μA at the bias voltage of-1 V, and the optical responsivity is 0.1 A/W at wavelength of 1.55 μm. The 3 dB bandwidth （BW） of 4 GHz is obtained for the photodetector with diameter of 24 μm at reverse bias voltage of 1 V. The long diffusion time of minority carrier in n-type Ge and the large contact resistance in metal/Ge contacts both affect the performance of Ge photodetectors.
基金funded by the National Natural Science Foundation of China (U1432249)the National Key R&D Program of China (2017YFA0205002)+3 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD)supported by Collaborative Innovation Center of Suzhou Nano Science & Technology and Joint International Research Laboratory of Carbon-Based Functional Materials and Devicesthe support from China Postdoctoral Science Foundation (2017M610346)Natural Science Foundation of Jiangsu Province of China (BK20170343)
文摘Flexible and broadband photodetectors have drawn extensive attention due to their potential application in foldable displays, optical communications, environmental monitoring, etc. In this work, a flexible photodetector based on the crystalline PbS quantum dots(QDs)/ZnO nanoparticles(NPs) heterostructure was proposed. The photodetector exhibits a broadband response from ultraviolet-visible(UV-Vis)to near infrared detector(NIR) range with a remarkable current on/off ratio of 7.08×10^3under 375 nm light illumination.Compared with pure ZnO NPs, the heterostructure photodetector shows the three orders of magnitude higher responsivity in Vis and NIR range, and maintains its performance in the UV range simultaneously. The photodetector demonstrates a high responsivity and detectivity of4.54 A W-1and 3.98×10^12Jones. In addition, the flexible photodetectors exhibit excellent durability and stability even after hundreds of times bending. This work paves a promising way for constructing next-generation high-performance flexible and broadband optoelectronic devices.
基金supported by the National Nature Science Foundation of China (51372075)
文摘An ultraviolet （UV）-visible tunable photodetec- tor based on ZnO nanorod arrays （NAs）/perovskite hetero- junction solar cell structures is presented, in which the ZnO NAs are prepared using the hydrothermal method and an- nealed in different atmospheres. Based on solar cell structure perovskite photodetectors, it exhibited highly repeatable and stable photoelectric response characteristics. In addition, the devices with ZnO NAs annealed in a vacuum showed a high responsivity of about 1014 cm Hz1/2 W-1 in the visible region, whereas the devices with ZnO NAs annealed in air exhib- Red good detectivity in the UV region, especially at around 350 nm. Furthermore, when the annealing atmosphere of the ZnO nanorods was changed from vacuum to air, the domi- nant detection region of the photodetectors was altered from the visible to the ultraviolet region. These results enable po- tential applications of the ZnO NAs/perovskite photodetec- tors in ultraviolet and visible regions.
基金supported by the National Natural Science Foundation of China (Grant No. 50972007)the Beijing Municipal Natural Science Foundation (Grant No. 4092035)+3 种基金the National Basic Research Program of China (973 Program) of the Ministry of Science and Technology of China(Grant No. 2011CB932703)the National Science Fund for Distinguished Young Scholars (Grant No. 60825407)the Special Items Fund of the Beijing Municipal Commission of Educationthe Opened Fund of the State Key Laboratory of Integrated Optoelectronics
文摘A high performance heterojunction organic ultraviolet photodetector based on NPB and Bphen has been fabricated. A trans- parent conducting polymer PEDOT：PSS coated quartz substrate instead of ITO coated glass substrate as anode is propitious to detect shorter wavelength ultraviolet light. As a result, the device shows a low dark current density, a high responsivity of 502 mA/W and a detectivity of 2.67x1012 cm Hz1/Zfw which is illuminated by a 220 nm ultraviolet light with an intensity of 1.6 mW/cm2. Moreover, the performance of the PEDOT：PSS transparent electrode device is better than the semi-transparent A1 electrode device electrode because of the higher transmittance and electrode properties.
基金the National Natural Science Foundation of China(51972101 and 11874143)the Natural Science Foundation of Hubei Province(2019CFB508)Wuhan Yellow Crane Talent Program(2017-02)。
文摘As a lead-free perovskite,CsBi3I10 has attracted significant attention because of its high thermal tolerance and long electron diffusion length.Solution-processed high-performance CsBi3I10 perovskite devices,however,are hindered by the formation of a two-dimensional structure,which results in an extremely high surface roughness and many pinholes.In this paper,we reported a space-confined growth(SCG)method using a single-layer polystyrene(PS)sphere template to obtain high-smoothness,high-crystallinity,and dense CsBi3I10 perovskite films.Compared with traditionally spin-coated CsBi3I10 photodetectors(PDs),the metal-semiconductor-metal PDs made by SCG showed a higher photocurrent,a lower dark current,and a bigger on/off ratio.In addition,the photocurrent of our unencapsulated CsBi3I10 perovskite PDs was not attenuated under long-time illumination.In addition,when the device was stored in air for 30 d,its performance also showed no degradation,demonstrating ultra-high stability.Furthermore,the synthesis was free of antisolvents,such as chlorobenzene and toluene,which is beneficial for the environmentally friendly assembly of the devices.Our strategy opens up a new way to prepare high-quality lead-free perovskite,which may be useful for applications in light-emitting diodes and solar cells.
基金financially supported by the National Natural Science Foundation of China (51761145048, 61725401 and 61704097)the Innovation Fund of WNLO and the 62th China Postdoctoral Science Foundation (2017M622418)
文摘Linearly bonded triiodide chains with fairly small distance between the adjacent iodine ions feature a facile electron transfer and highly anisotropic properties.Here,we demonstrate a novel strategy towards a new one-dimensional linear triiodide DMEDA·I6,using chain-type N,N'-dimethylethanediamine(DMEDA)cation to coordinate triiodine ions.This triiodide has the shortest distance between adjacent I3^- and good linearity.An estimated electronic band gap of1.36 e V indicates its semiconducting properties.100 fold differences both in polarization-sensitive absorption and effective mass were achieved by simulation,with directions parallel and perpendicular to the a-axis of DMEDA·I6.The DMEDA·I6 single crystal-based photodetectors show a good switching characteristic and a distinct polarization-sensitive photoresponse with linear dichroic photodetection ratio of about 1.9.Strongly anisotropic features and semiconducting properties of DMEDA·I6 make this triiodide system an interesting candidate for polarization related applications.
基金supported by the National Natural Science Foundation of China (61574132 and 61625404)
文摘A simple self-catalyzed chemical vapor deposition process was conducted to synthesize single-crystalline GaSb nanowires,where Ga droplets were utilized as the catalysts.The as-grown GaSb nanowires exhibited typical p-type semiconductor behavior with the calculated hole mobility of about 0.042 cm^2 V^-1 s^-1.The photoresponse properties of the GaSb nanowires were studied by fabricating nanowire photodetectors on both rigid and flexible substrates.The results revealed that the photodetectors exhibited broad spectral response ranging from ultraviolet,visible,to near-infrared region.For the device on rigid substrate,the corresponding responsivity and the detectivity were calculated to be 3.86×10^3 A W-1 and 3.15×10^13 Jones for 500 nm light,and 7.22×10^2 A W-1 and 5.90×10^12 Jones for 808 nm light,respectively,which were the highest value compared with those of other reported Ga1-xInxAsySb1-y structure nanowires.Besides,the flexible photodetectors not only maintained the comparable good photoresponse properties as the rigid one,but also possessed excellent mechanical flexibility and stability.This study could facilitate the understanding on the fundamental characteristics of self-catalyzed grown GaSb nanowires and the design of functional nano-optoelectronic devices based on GaSb nanowires.
