- 标题
- 摘要
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- 实验方案
- 产品
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Dynamics and spectral characteristics of quantum dot semiconductor lasers under optical injection locking
摘要： The operation of an injection-locked quantum dot laser including the output characteristics, modulation response, and linewidth enhancement factor (LEF) has been investigated in detail considering the effect of homogeneous and inhomogeneous broadenings. Results demonstrate that a single-mode operation is guaranteed for a broad range of homogeneous broadening values (operation temperatures). Injection power-dependant reduction in the threshold current and a large increase in the slope efficiency and the output power have been achieved. Also, a near-zero and uniform LEF is obtained for the whole lasing spectra where drastic reduction from ~60 to 0.76 is observed for non-injected modes. The device exhibits a reduced settling time and modified modulation response especially a reduced frequency overshoot and enhanced 3dB modulation bandwidth. Obtained characteristics provide a design degree of freedom for spectral shaping and single/multi-mode operation which are favorable features for optical signal processing applications.
关键词： Optical injection locking,linewidth enhancement factor,modulation response
更新于2025-09-23 15:19:57
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Investigation of optical fiber-tip probes for common and ultrafast SERS
摘要： In this study, we performed a three-dimensional computational experiment on ultrashort pulse propagation in an optical fiber-tip probe that is decorated with gold nanoparticles (NPs) using a constant structure for the probe’s dielectric taper and different spatial configurations of the gold nanoparticles. Interestingly, a hot spot with the highest amplitude of the electric field was found not along the same chain of the NPs but between terminal NPs of neighboring chains of NPs at the probe’s tip (the amplitude of the electric field in the hot spots between the NPs along the same chain was of the order of 101, while that between terminal NPs of neighboring chains was of the order of 103). We eventually identified a configuration with only six terminal nanoparticles (Config4) which is characterized by the highest electric field amplitude enhancement and can provide the highest spatial resolution in the SERS interrogation of an object of interest. The ultrashort temporal responses of the hot spots for all configurations exhibited relatively high pulse elongation (relative elongation was greater than 4.3%). At the same time, due to the reflection of the incident pulse and consequent interference, the temporal responses of most hot spots contained several peaks for all configurations except for the optimum Config4. Nonetheless, the ultrashort temporal responses of all hot spots for Config4 were characterized by a single peak but with a relatively large pulse elongation (relative elongation was 234.1%). The results indicate that further examination of this new structure of a nanoparticles-coated optical fiber-tip probe with only six terminal NPs may provide attractive characteristics for its practical applications.
关键词： gold nanoparticles,femtosecond pulse,optical fiber-tip probe,ultrafast nanophotonics.,surface-enhanced Raman spectroscopy,temporal response
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE) - Melacca, Malaysia (2019.11.25-2019.11.27)] 2019 IEEE Asia-Pacific Conference on Applied Electromagnetics (APACE) - 3D Printed Waveguide Phase Shifter for Butler Matrix Network
摘要： The smart grid vision has resulted in many demand side innovations such as nonintrusive load monitoring techniques, residential micro-grids, and demand response programs. Many of these techniques need a detailed residential network model for their research, evaluation, and validation. In response to such a need, this paper presents a sequential Monte Carlo (SMC) simulation platform for modeling and simulating low voltage residential networks. This platform targets the simulation of the quasi-steady-state network condition over an extended period such as 24 h. It consists of two main components. The first is a multiphase network model with power flow, harmonic, and motor starting study capabilities. The second is a load/generation behavior model that establishes the operating characteristics of various loads and generators based on time-of-use probability curves. These two components are combined together through an SMC simulation scheme. Four case studies are presented to demonstrate the applications of the proposed platform.
关键词： power quality,network simulation,microgrids,Demand response,low voltage residential networks
更新于2025-09-23 15:19:57
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Fast-Response and Self-Powered Cu <sub/>2</sub> O/ZnO Nanorods Heterojunction UV-Visible (570 nm) Photodetectors
摘要： A fast, self-powered photodetector (PD) capable of UV to visible (570 nm) sensing based on the p-Cu2O/n-ZnO nanorods (NRs) heterostructure is reported. The PD shows a spectral response range from 380 nm to 570 nm, which is suitable for ambient light sensing applications. The PD exhibits good rectifying characteristics with a low leakage current and a low turn-on voltage of ～0.3 V. The responsivities of the self-powered PD are 0.24 A W?1 and 0.06 A W?1 at 380 and 450 nm, respectively. The rise/recovery time of the PD are 0.02/0.03 s and 0.01/0.02 s for UV (370 nm) and visible light (450 nm), respectively. Upon UV light illumination, the long, persistent photocurrent (or recovery time) caused by ZnO NRs can be eliminated using the self-powered mode.
关键词： fast-response,p-Cu2O/n-ZnO nanorods heterostructure,self-powered photodetector,UV-Visible sensing
更新于2025-09-23 15:19:57
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Quantifying the Relationship Between Higher Photovoltaic Module Efficiency and the Adoption of Distributed Solar
摘要： Some applications of data from the Clouds and the Earth’s Radiant Energy System (CERES) scanning radiometer require the use of the point response function (PRF), which describes the influence of radiance from each point on the measurement. A radiance source for the measurement of the PRF of the CERES instruments was built and installed into the Radiometric Calibration Facility, in which the CERES instruments have been calibrated. The design and application of the PRF source and the computation of the PRF from these measurements are described. In order to compare the PRF based on measurements with the theoretical PRF, it is necessary to account for the finite size of the beam from the source. The use of the PRF source and the analysis of the data are demonstrated by application to the FM-5 instrument. The measured results compare well with theory for the CERES instruments and are presented for FM-5.
关键词： Aqua,Terra,point spread function,radiometry,National Polar-orbiting Partnership (NPP),Earth radiation budget,point response function (PRF),calibration,Clouds and the Earth’s Radiation Energy System (CERES)
更新于2025-09-23 15:19:57
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Surface modification of AlN using organic molecular layer for improved deep UV photodetector performance
摘要： Direct wide bandgap of 6.2 eV, high temperature robustness and radiation hardness make aluminum nitride (AlN) a preferable semiconductor for deep ultraviolet (UV) photodetection. However, the performance and reliability of AlN- based devices is adversely affected by a large density of surface states present in AlN. In this work, we have investigated the potential of a monolayer of organic molecules in passivating the surface states of AlN which improved the performance of AlN- based metal- semiconductor- metal (MSM) deep UV photodetectors. The organic molecules of Meso-5,10,15-triphenyl-20-(p-hydroxyphenyl)porphyrin Zn(II) complex (ZnTPP(OH)) were successfully adsorbed on AlN surface, forming a self- assembled monolayer (SAM). The molecular layer was characterized by contact angle measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The surface modification of AlN effectively reduced dark current of the photodetector by ten times without degrading the magnitude of photo current, especially at low voltages. Photo to dark current ratio (PDCR) was enhanced from 930 to 7835 at -2V and the responsivity doubled from 0.3 mA/W to 0.6 mA/W at 5V. Moreover, the rise and fall times of the detector were found to decrease after the surface modification process. Our results suggest that SAM of porphyrin molecules effectively passivated the surface states in AlN which resulted in improved photodetector performance.
关键词： Dark current,PDCR,MSM UV photodetector,Surface states,SAM,Responsivity,Temporal response
更新于2025-09-23 15:19:57
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Novel synthesis of Cu2CoSnS4-carbon quantum dots (CCTS:CQD) nano-composite potential light absorber for hybrid photovoltaics
摘要： A novel and simple synthesis of the absorber layer is indispensable in order to reduce the cost and processing of quantum solar cells. In this work, we developed novel Cu2CoSnS4-carbon quantum dot (CCTS:CQD) nano-composite as an absorbing material for solar cell applications. CCTS:CQD nano-composites were prepared by direct pyrolysis of CCTS precursors and citric acid. The proportions of citric acid precursor to CCTS were varied from 0.1 to 0.7. The properties of the synthesized nano-composite were studied using a UV-Vis spectrophotometer in the wavelength range of 300-900 nm. CCTS:CQD has a property of dynamic photoluminescence that depends on the excitation wavelength. The results of the X-ray diffraction revealed that the CCTS:CQD nano-composites were predominantly polycrystalline in nature. The formation of CCTS:CQD was confirmed by a high-resolution transmission electron microscope (HRTEM), which exhibits the size ~3 nm. The thin films of CCTS:CQD nano-composites were deposited on glass/ITO substrates by spray pyrolysis technique at 170 °C. Current-voltage (I-V) measurements carried out in dark and light conditions revealed CCTS:CQD thin films with good photo-response. The purpose of the present study is to develop CCTS:CQD nano-composite p-type absorber layer suitable for thin film solar cells.
关键词： quantum dot,photo-response,Thin Films,Nano-composites,Absorber
更新于2025-09-23 15:19:57
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Photon energy response optimization using few-channel spectroscopy dose method for Si-PIN photodetector applied in personal dose equivalent measurements
摘要： Si-PIN photodetectors having features such as low cost, small size, low weight, low voltage, and low power consumption are widely used as radiation detectors in electronic personal dosimeters (EPDs). The technical parameters of EPDs based on the Si-PIN photodetectors include photon energy response (PER), angular response, inherent error, and dose rate linearity. Among them, PER is a key parameter for evaluation of EPD measurement accuracy. At present, owing to the limitations of volume, power consumption, and EPD cost, the PER is usually corrected by a combination of single-channel counting techniques and filtering material methods. However, the above-mentioned methods have problems such as poor PER and low measurement accuracy. To solve such problems, in this study, a 1024-channel spectrometry system using a Si-PIN photodetector was developed and full-spectrum measurement in the reference radiation fields was conducted for radiation protection. The measurement results using the few-channel spectroscopy dose method showed that the PER could be controlled within ± 14% and ± 2% under the conditions of two and three energy intervals, respectively, with different channel numbers. The PER measured at 0° angle of radiation incidence meets the IEC 61526:2010 - 29% to +67% requirements of. Meanwhile, the channel number and counts-to-dose conversion factors formed in the experiment can be integrated into an EPD.
关键词： Si-PIN photodetector,Personal dose equivalent,Photon energy response,Electronic personal dosimeter,Few-channel spectroscopy dose method
更新于2025-09-23 15:19:57
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Highly sensitive, broadband, fast response organic photodetectors based on semi-tandem structure
摘要： Solution-processed organic photodetectors (OPDs) simultaneously integrating high performance by solution-processability. The semi-tandem structure directly superimposes two active layers with complementary absorption spectra, achieving a broad spectral response of 300-1000 nm. It provides a detection covering from ultraviolet to near-infrared range, while the external quantum efficiency in the spectral range of 550 nm to 950 nm retains 70 %. The high electron and hole injection barriers enable a dark current density as low as 6.51×10-5 mA cm-2 at -0.1 V, resulting in a noise current of 3.91×10-13 A Hz-1/2 at 70 Hz, which is nearly three times lower than single-junction photodetectors. Encouragingly, the device response speed is improved by suppressing the resistance-capacitance time constant of the device employing semi-tandem structure induced capacitance decreasing. The state-of-the-art OPDs contribute to the response time of 26.27 ns, which is the fastest one in OPDs to the best of our knowledge. We believe that the semi-tandem structures provide a new approach to achieving high-performance photodetectors integrating fast, sensitive and broadband response.
关键词： broadband,ultra-fast response,Organic photodetectors,semi-tandem structure
更新于2025-09-23 15:19:57
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Inverted pyramid Er3+ and Yb3+ Co-doped TiO2 nanorod arrays based perovskite solar cell: Infrared response and improved current density
摘要： In this study, a Yb3+, Er3+ co-doped TiO2 inverted pyramid nanorod (NR) array and a compact TiO2 ?lm are simultaneously fabricated as the mesoporous support layer and electron-blocking layer, respectively, by a one-pot hydrothermal method. The scanning electron microscopy results show that the incorporation of Er3+ and Yb3+ causes changes not only in the growth rate of the NRs, but also in the TiO2 NR morphology. The Er3+, Yb3+ co-doped TiO2 NRs exhibit an inverted pyramidal morphology, which is bene?cial for perovskite permeation and light utilization. Notably, the Er3+, Yb3+ co-doping causes changes in the band gap of TiO2 and leads to 25% increase in the current density. The electrochemical impedance spectroscopy results show that the device based on the doped TiO2 NRs has a higher recombination resistance and a lower transfer resistance than those of the undoped device, and thereby, the doped device exhibits a lower electron recombination rate. In addition, the upconversion Er and Yb co-doped device exhibits 25% higher current density and 17% higher photon-to-electron conversion e?ciency, as revealed by the J-V test results. Moreover, the optimized e?ciency of the TiO2 NR array-based perovskite solar cell is determined to be 10.02%. Furthermore, the Er and Yb co-doped device exhibits a near-infrared response, an e?ciency of 0.1% is achieved under infrared light (800–1100 nm) irradiation. This upconversion material can widen the photovoltaic responses of solar cells into the near-infrared region and improve the utilization of sunlight.
关键词： Infrared response,Yb3+,Er3+ co-doped,TiO2 nanorods,Perovskite solar cell
更新于2025-09-23 15:19:57