- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
High performance Zn-diffused planar mid-wavelength infrared type-II InAs/InAs <sub/>1a??x</sub> Sb <sub/>x</sub> superlattice photodetector by MOCVD
摘要： We report a Zn-diffused planar mid-wavelength infrared photodetector based on type-II InAs/InAs1?xSbx superlattices. Both the superlattice growth and Zn diffusion were performed in a metal-organic chemical vapor deposition system. At 77 K, the photodetector exhibits a peak responsivity of 0.70 A/W at 3.65 μm, corresponding to a quantum efficiency of 24% at zero bias without anti-reflection coating, with a 50% cutoff wavelength of 4.28 μm. With an R0A value of 3.2 × 105 Ω cm2 and a dark current density of 9.6 × 10?8 A/cm2 under an applied bias of ?20 mV at 77 K, the photodetector exhibits a specific detectivity of 2.9 × 1012 cm Hz1/2/W. At 150 K, the photodetector exhibits a dark current density of 9.1 × 10?6 A/cm2 and a quantum efficiency of 25%, resulting in a detectivity of 3.4 × 1011 cm Hz1/2/W.
关键词： specific detectivity,metal-organic chemical vapor deposition,type-II InAs/InAs1?xSbx superlattices,quantum efficiency,Zn-diffused planar mid-wavelength infrared photodetector
更新于2025-09-23 15:19:57
-
IMPROVING THE QUALITY OF PHOTODETECTORS USING ISOTOPIC NANOENGINEERING METHODS
摘要： The study considers the possibility of changing the isotopic composition of a substance to improve the physical properties of the material and the optoelectronic characteristics of a photodetector as the most common device in optoelectronics. It is shown that the reduction of heavy isotopes in the semiconductor material of photodetectors increases the mobility of charge carriers, the light absorption coefficient, and quantum efficiency, while reducing the number of band gap sublevels that affect the dark current. This increases the photodetector sensitivity, decreases the magnitude of the dark current, and improves the signal power to noise power ratio at the output of the photodetector. Technologies for improving the properties of a material by improving the characteristics of bulk semiconductor crystals, multiple quantum wells, and superlattices are compared.
关键词： optoelectronics,photodetectors,quantum efficiency,isotopic nanoengineering,semiconductor materials
更新于2025-09-23 15:19:57
-
Photoelectric properties of SnO2: Ag/Pa??Si heterojunction photodetector
摘要： N-type Tin dioxide thin films with thickness (350 nm) prepared by thermal evaporation method. The thin film SnO2 was doped with Ag by the rate (0.01, 0.02 and 0.03). Atomic Force Microscopic (AFM) was adopted to determine the grain size and roughness of the film surface. The electrical properties were determined by mean of Hall Measurement system and mobility was calculated. SnO2: Ag/P–Si photodetectors demonstration the highest described visible responsivity of (0.287 A/W) with the Ag ratio of (0.03). I–V characteristics with different power density were measured. The best sensitive value of the spectral response, specific detectivity and quantum efficiency at wavelength (422 nm).
关键词： Ag/P–Si,Quantum efficiency,Detector,SnO2,Mobility
更新于2025-09-23 15:19:57
-
All-fluorescent white organic light-emitting diodes with EQE exceeding theoretical limit of 5% by incorporating a novel yellow fluorophor in co-doping forming blue exciplex
摘要： For all-fluorescent white organic light-emitting diodes (WOLEDs), it is a current challenge to achieve comparable device efficiency to phosphorescent devices. A novel yellow fluorophor (Y), synthesized by our group, realizes ultra-high electroluminescence performance with maximum luminance and external quantum efficiency (EQE) reaching 74820 cd/m2 and 5.65%, respectively, indicating a huge potential applications in developing high-performance all-fluorescent WOLEDs. Herein, we employ above yellow emitter Y to demonstrate a series of all-fluorescent WOLEDs, where the devices are fabricated by doping yellow emitter Y in blue-emitting thermally activated delayed fluorescent (TADF) host of mCP:PO-T2T-forming exciplex. And white emission are realized by the combination of blue and yellow emissions from mCP:PO-T2T host and yellow emitter Y through the incomplete energy transfer. By simply adjusting the doping ratio of yellow emitter Y in mCP:PO-T2T host, the optimized all-fluorescent white device achieves high device performance with maximum current efficiency, power efficiency, and EQE reaching 20.78 cd/A , 24.25 lm/W, and 8.22%, respectively. The EQE obviously exceed the theoretical limit value of 5% for all-fluorescent WOLEDs, and is comparable to some fluorescent/phosphorescent or all-phosphorescent WOLEDs in reported literatures. The achievement of such high performance is mainly ascribed to the highly efficient exciton utilization derived from excellent yellow fluorescent emitter Y and effective reverse intersystem crossing (RISC) from triplet level to singlet level in mCP:PO-T2T exciplex host.
关键词： white emission,exciplex host,all-fluorescent emission,organic light-emitting diodes,external quantum efficiency
更新于2025-09-23 15:19:57
-
The Role of Delocalization and Excess Energy in the Quantum Efficiency of Organic Solar Cells and the Validity of Optical Reciprocity Relations
摘要： The photon energy dependence of long-range charge separation is studied for two prototypical polymer:fullerene systems. The internal quantum efficiency (IQE) of PCDTBT:PC61BM is experimentally shown to be independent on the excitation energy. In contrast, for TQ1:PC71BM the IQE is strongly energy-dependent for excitation energies close to CT electroluminescence peak maximum while it becomes energy-independent at higher excitation energies. Kinetic Monte Carlo simulations reproduce the experimental IQE and reveal that the photon energy-dependence of the IQE is governed by charge delocalization. Efficient long-range separation at excitation energies corresponding to the CT electroluminescence peak maximum or lower requires an initial separation of the hole-electron pair by ～4-5nm, whereas delocalization is less important for charge separation at higher photon energies. Our modeling results suggest that a phenomenological reciprocity between CT electroluminescence and external quantum efficiency does not necessarily prove that commonly employed reciprocity relations between these spectra are valid from a fundamental perspective.
关键词： delocalization,optical reciprocity relations,quantum efficiency,organic solar cells,charge separation
更新于2025-09-23 15:19:57
-
Method for Measuring the Absolute Spectral Response of Infrared Photodetector Arrays
摘要： Physical and technical aspects of the implementation of an alternative method for measuring the absolute spectral response of infrared photodetector arrays (IR PDA) (current sensitivity spectrum, voltage sensitivity, and quantum efficiency) without the use of spectral instruments are considered. The method is based on multiple measurements of the output signal of all IR array’s photosensitive elements (PSEs) generated by modulated black-body radiation at different temperatures of the black body (BB). The signal is measured against the sum of constant signals from the background radiation, the detector input optical window, the BB radiation modulator, the PSE dark current, and the constant signal of the LSI multiplexer. A system of Fredholm integral equations of the first kind is constructed based on the measured PSE signals. Its left side includes measured BB signals and, the right side, analytical expressions describing these signals. The solution of the system are the absolute values of the above-mentioned spectral components of all PSEs of PDAs. The block diagram of the measurement setup is considered, functional features of its operation are analyzed, and requirements for its blocks are substantiated. Additional advantages of the new method in comparison with the existing methods are presented.
关键词： useful and stray irradiation,current and voltage sensitivity spectra,PSE red boundary histogram,PSE red boundary distribution on IR array area,BB radiation modulation,IR PDA output signal,quantum efficiency spectrum
更新于2025-09-23 15:19:57
-
High Responsivity and External Quantum Efficiency Photodetectors Based on Solution-Processed Ni-Doped CuO Films
摘要： Photodetectors based on p-type metal oxides are still a challenge for optoelectronic device applications. Many effects have been paid to improve the performance and expand the detection range. Here, high-quality Cu1-xNixO (x=0, 0.2, and 0.4) film photodetectors were prepared by a solution process. The crystal quality, morphology, and grain size of Cu1-xNixO films can be modulated by Ni doping. Among the photodetectors, the Cu0.8Ni0.2O photodetector shows the maximum photocurrent value (6×10-7 A) under 635 nm laser illumination. High responsivity (26.46 A/W) and external quantum efficiency (5176 %) are also achieved for Cu0.8Ni0.2O photodetector. This is because the Cu0.8Ni0.2O photosensitive layer exhibits high photoconductivity, low surface states, and high crystallization after 20% Ni doping. Compared to the other photodetectors, the Cu0.8Ni0.2O photodetector exhibits the optimal response in the near-infrared region, owing to the high absorption coefficient. These findings provide a route to fabricate high performance and wide detection range p-type metal oxide photodetectors.
关键词： Copper oxide,Ni doping,photodetector,responsivity,external quantum efficiency
更新于2025-09-23 15:19:57
-
Comparison of size-dependent characteristics of blue and green InGaN microLEDs down to 1a?? <b> <i>??</i> </b> m in diameter
摘要： There is growing interest in microLED devices with lateral dimensions between 1 and 10 lm. However, reductions in external quantum ef?ciency (EQE) due to increased nonradiative recombination at the surface become an issue at these sizes. Previous attempts to study size-dependent EQE trends have been limited to dimensions above 5 lm, partly due to fabrication challenges. Here, we present size-dependent EQE data for InGaN microLEDs down to 1 lm in diameter fabricated using a process that only utilizes standard semiconductor processing techniques (i.e., lithography and etching). Furthermore, differences in EQE trends for blue and green InGaN microLEDs are compared. Green wavelength devices prove to be less susceptible to reductions in ef?ciency with the decreasing size; consequently, green devices attain higher EQEs than blue devices below 10 lm despite lower internal quantum ef?ciencies in the bulk material. This is explained by smaller sur- face recombination velocities with the increasing indium content due to enhanced carrier localization.
关键词： InGaN,microLEDs,size-dependent characteristics,external quantum efficiency,blue and green wavelengths
更新于2025-09-23 15:19:57
-
(Ba,Sr)LaZnTaO6:Mn4+ far red emission phosphors for plant growth LEDs: structure and photoluminescence properties
摘要： It is necessary to develop novel high-efficient red or far-red-emitting in order to facilitate the phosphor-converted light-emitting diodes (pc-LEDs) for plant growth. This work reports a series of novel far-red emitting (Ba,Sr)LaZnTaO6:xMn4+ phosphors with double perovskite structure synthesized by traditional high-temperature solid-state reaction (SSR) process. The crystal structure and morphology of (Ba,Sr)LaZnTaO6 are investigated by high-resolution TEM, SEM, and XRD Rietveld refinement. The photoluminescece properties are systematically explored and analyzed by diffuse reflection (DR) spectra, photoluminescence emission (PL) and excitation (PLE) spectra, decay curves and temperature-dependent spectra. Mn4+ ions occupy Ta5+ sites located at [TaO6] octahedral emitting red light with peak at 698 nm in BaLaZnTaO6:Mn4+ and 695 nm in SrLaZnTaO6:Mn4+ under n-UV and blue light excitation. The critical quenching concentration of Mn4+ was determined to be 0.008. The concentration quenching mechanism could be a dipole-dipole interaction between Mn4+ ions. In addtion, the PL intensity of (Ba,Sr)LaZnTaO6:xMn4+ phosphors decrease with increasing temperature. The SrLaZnTaO6:xMn4+ sample has better thermal stability than BaLaZnTaO6:xMn4+. Interestingly, (Ba,Sr)LaZnTaO6:0.008Mn4+ exhibits outstanding internal quantum efficiency (IQE ≥ 80 %). Fianally, the fabricated of LEDs are combined with SrLaZnTaO6:0.008Mn4+ phosphors combined with 460 nm InGaN chips, which emit blue and red light. Based on above properties, the rare-earth-free (Ba,Sr)LaZnTaO6:xMn4+ phosphors have great potentials to be serviced as far-red emitting phosphors in high-power plant growth LEDS.
关键词： double perovskite structure,phosphor-converted light-emitting diodes,internal quantum efficiency,far-red emitting,plant growth,Mn4+,thermal stability,photoluminescence,solid-state reaction
更新于2025-09-23 15:19:57
-
Hybrid chemical bath deposition-CdS/sputter-Zn(O,S) alternative buffer for Cu <sub/>2</sub> ZnSn(S,Se) <sub/>4</sub> based solar cells
摘要： To replace the conventionally used CdS buffers in Cu2ZnSn(S,Se)4 (CZTSSe) based thin-film solar cells, sputtered Zn(O,S) buffer layers have been investigated. Zn(O,S) layers with three different [O]/([O] + [S]) ratios (0.4, 0.7, and 0.8)—and a combination of Zn(O,S) and CdS (“hybrid buffer layer”) were studied. In comparison to the CdS reference, the external quantum efficiency (EQE) of the Zn(O,S)-buffered devices increases in the short- and long-wavelength regions of the spectrum. However, the average EQE ranges below that of the CdS reference, and the devices show a low open-circuit voltage (VOC). By adding a very thin CdS layer (5 nm) between the absorber and the Zn(O,S) buffer, the VOC loss is completely avoided. Using thicker intermediate CdS layers result in a further device improvement, with VOC values above those of the CdS reference. X-ray photoelectron spectroscopy (XPS) measurements suggest that the thin CdS layer prevents damage to the absorber surface during the sputter deposition of the Zn(O,S) buffer. With the hybrid buffer configuration, a record VOC deficit, i.e., a minimum difference between bandgap energy Eg (divided by the elementary charge q) and VOC (Eg/q – VOC) of 519 mV could be obtained, i.e., the lowest value reported for kesterite solar cells to date. Thus, the hybrid buffer configuration is a promising approach to overcome one of the main bottlenecks of kesterite-based solar cells, while simultaneously also reducing the amount of cadmium needed in the device.
关键词： VOC deficit,Cu2ZnSn(S,Se)4,CdS,hybrid buffer layer,open-circuit voltage,X-ray photoelectron spectroscopy,thin-film solar cells,Zn(O,S) buffer layers,external quantum efficiency
更新于2025-09-23 15:19:57