最新刊期
卷 46 ， 期 4 ， 2025
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Design and Optimization of Highly Efficient Light Extraction Encapsulation for Deep Ultraviolet LEDs 增强出版
摘要：To face the challenge of low light extraction in AlGaN-based deep ultraviolet （DUV） LEDs， a quartz lens encapsulation structure bonded with fluorine resin was designed to effectively resolve the significant internal total reflection （ITR） losses when photons emitted from the sapphire substrate of the flip-chip LED. This work demonstrated that the thin interfacial fluorine resin bonding layer could form a matched refractive index transition layer， maximizing light extraction. For typical 250 nm DUV LEDs， 28% light output intensity could be enhanced. Additionally， a ceramic packaging substrate with reflective sidewalls was designed to improve the extraction and convergence of transverse magnetic （TM）-mode emission from the DUV LEDs. Simulation results indicated significant improvements across different wavelengths of DUV LEDs. Compared to the reference sample （<50% forward light output efficiency）， the design of reflective packaging substrates could raise the efficiency to 94%. The efficiency enhancement was more significant for LEDs with ≤250 nm wavelengths， caused by the higher proportion of TM-mode emission. Further optimization of the quartz lens curvature was able to effectively manipulate the emission convergence characteristics for LEDs， which meet the light field distribution requirements for various applications such as surface disinfection.关键词：AlGaN;deep ultraviolet LEDs;light extraction;encapsulation structure149|166|0更新时间：2025-04-21
Cover Story
- 摘要：Zinc magnesium oxide （ZnMgO）， a ternary alloy constituted of wide bandgap semiconductor materials zinc oxide （ZnO） and magnesium oxide （MgO）. As a direct bandgap semiconductor， theoretically， its bandgap width can be continuously tuned between 3.37 eV of ZnO and 7.8 eV of MgO. It possesses numerous properties such as abundant nanostructures， low preparation temperature， strong radiation resistance， and high stability， making it an excellent detection material for ultraviolet photodetectors. Moreover， apart from the aforementioned advantages， ZnMgO also exhibits rich physical properties such as piezoelectricity， pyroelectricity， and ferroelectricity， which provide new possibilities for the expansion of the applications in ultraviolet detectors. Consequently， related research has become a hotspot in the field of ultraviolet detection in recent years. In view of this， this thesis comprehensively reviews the material properties of ZnMgO， focusing on the research progress in bandgap engineering， ferroelectric/pyroelectric/piezoelectric polarization， and low-dimensional structures in the structural design， performance regulation， and application development of its ultraviolet detection devices.关键词：Zinc Magnesium Oxide;Ultraviolet Photodetectors;Bandgap Engineering;Wurtzite Ferroelectricity;flexible devices46|66|0更新时间：2025-04-21
- 摘要：As one of the best-known n-type metal oxides in third-generation semiconductor electronic devices， in particular， with its high detection rate， high optical gain， and high sensitivity， ZnO is commonly used in the construction of high-performance ultraviolet photodetectors. The photoconductivity behavior of zinc oxide strongly depends on its surface interface properties， the trapping and detrapping of photogenerated carriers by defect states near the conduction band. Researches have found that persistent photoconductivity and even negative photoconductivity（NPC） effects can be observed in ZnO devices due to carrier loss and defect trapping. This paper starts from the positive photoconductivity mechanism of ZnO devices， and provides a detailed introduction to the negative photoconductivity phenomena observed in ZnO-based devices under different preparation conditions and ambient temperatures， different driving methods， dielectric recombination， and heterostructures， as well as the microscopic physical mechanisms responsible for the negative photoconductivity effect. Underlying the NPC effect of ZnO can provide a feasible approach for constructing highly efficiency logic circuits， light-emitting diodes， solar cells， and ultra-high resolution imaging sensors.关键词：zinc oxide;optoelectronic properties;negative photoconductivity124|119|0更新时间：2025-04-21
- 摘要：ZnO is a typical third-generation semiconductor with a wide bandgap of 3.37 eV. Intrinsic ZnO is an n-type semiconductor， and the use of donor element doping technology can significantly enhance its n-type conductivity. ZnO-based transparent conductive thin films have the advantages of abundant raw material sources， diverse preparation methods， and room temperature growth， which can be applied in many fields such as optoelectronics， sensing， photothermal， etc. Among them， Al doped ZnO （AZO） is a typical transparent conductive oxide （TCO）， which has attracted much attention in recent years. This article takes AZO thin film as the main representative and summarizes the latest research progress of ZnO based transparent conductive films， including the physical and chemical properties of different types of transparent conductive thin films such as doped ZnO single-layer thin films， ZnO based multi-layer thin films， and flexible ZnO based thin films. We focus on the optoelectronic properties （e.g.， mobility， bandgap width， transmittance/absorption/reflectivity） of ZnO based transparent conductive films， exploring their inherent relationships. The practical applications are introduced in detail for ZnO based transparent conductive films in the fields of light-emitting diodes， solar cells， sensors， semiconductor heating， and so on. The existing challenges and future development trends are also discussed.关键词：zinc oxide;transparent conductive film;Donor doping;AZO;Optoelectronic properties81|124|0更新时间：2025-04-21
- 摘要：Photoelectrochemical （PEC） sensors have the advantages of low background signal， fast response， and high sensitivity， and play an important role in environmental protection and public health. Zinc oxide （ZnO）， as a photoelectric material with high carrier concentration， favorable biocompatibility， and stable structure， has been widely used in the field of PEC sensing in recent years. This paper reviews the research progress of ZnO and its nanocomposites in the field of PEC sensing. First， the steps for controlling the structure of ZnO are introduced from three aspects： morphology regulation， utilization of piezoelectric effect， and introduction of defect engineering. Second， the applications of metal sensitized ZnO for PEC sensing from precious metals and metalloids are summarized， and the strategies for coupling semiconductors with ZnO to construct heterojunctions are sorted out. On this basis， the application progress of ZnO based ternary composites for PEC sensing is introduced. Finally， based on the current status and future requirements of ZnO in the field of PEC sensing， the prospect of realizing high-performance and multifunctional ZnO-based PEC sensors is discussed.关键词：zinc oxide;Photoelectrochemistry;sensing;research progress171|222|0更新时间：2025-04-21
- 摘要：Scintillation imaging screens are critical components in X-ray imaging technology. The accurate measurement of their light yield plays a pivotal role in improving the spatial resolution of imaging systems and advancing the development of new scintillators. This paper first provides an overview of the basic principles of X-ray imaging technology， followed by a review of the main methods for measuring light yield in X-ray imaging scintillators. These methods include relative measurement techniques based on energy spectra and X-ray excitation spectra， as well as absolute measurement methods using photomultiplier tubes （PMTs） and photodiodes （PDs） or avalanche photodiodes （APDs）. Additionally， this paper summarizes the potential impacts of various factors on light yield measurements， such as packaging and coupling technologies， the energy characteristics of the radiation source， particle types， and the types of photodetectors used for light yield measurements. Furthermore， an absolute light yield measurement method is proposed based on correcting the light collection efficiency. This method effectively combines the advantages of the absolute measurement techniques using PMTs and PDs， achieving wide-range light yield measurements （covering light outputs at the hundred-photons level） while maintaining a low measurement uncertainty of 5%.关键词：scintillating imaging screens;light yield;measurement methods;uncertainty optimization126|167|0更新时间：2025-04-21
- 摘要：Radiation damage is a common core problem in various fields， such as medical imaging， large-scale scientific facilities， aerospace industry， etc. The study of high-energy radiation stability and damage mechanism of materials is an essential step for their practical application. As new semiconductor materials， perovskites have shown great application prospects in high-energy radiation detection. However， the high-energy radiation stability of perovskite materials is still controversial and the radiation damage mechanism is not clear yet. This paper discusses the damage mechanism of perovskites in high-energy radiation environments and identifies the primary factors affecting their radiation stability. Additionally， potential strategies to enhance the radiation resistance of perovskites are proposed. The study aims to elucidate the structure-activity relationship between structure and radiation stability of perovskite， providing valuable insights for the development of perovskite-based radiation detectors.关键词：perovskite;irradiation stability;damage mechanism106|206|0更新时间：2025-04-21
Invited Paper
- 摘要：CsPbBr3 perovskite nanocrystals possess outstanding green light emission and low-cost preparation， making them important materials that are expected to meet the color gamut requirements for ultra-high-definition displays. However， due to the influence of multiple factors such as the elemental composition ratio and size control， it is difficult for CsPbBr3 perovskite nanocrystals to form narrow green light emission near 530 nm， thus resulting in a significant deviation from the standard green light required by the Rec.2020 color gamut. In this work， CsPbBr3@BNQD nanocrystal composites were synthesized by introducing boron nitride quantum dots （BNQD） and glutaric acid ligands into the precursor solution of ligand-assisted reprecipitation to synergistically induce the growth of nanocrystals. The anchoring effect of glutaric acid ligands on the surface of nanocrystals and the wide bandgap characteristics of BNQD nanocrystals enable the prepared CsPbBr3@BNQD nanocrystal composites to exhibit narrow green light emission at 525 nm with a full width at half maximum （FWHM） of 15.9 nm and a high luminous efficiency of 78%. Moreover， its CIE coordinates （0.161， 0.790） basically coincide with the standard green coordinates of Rec.2020. In addition， the CsPbBr3@BNQD nanocrystal composites demonstrate good aging stability in the LED on-chip packaging application， providing an effective solution for the standard green light technology in ultra-high-definition displays.关键词：perovskite nanocrystals;boron nitride quantum dots;composite materials;Rec.2020 standard green light80|12|0更新时间：2025-04-21
Research Letter
- 摘要：Light-emitting diodes （LEDs） are the core components of new display technology and the leader of the new generation of information technology industry. Perovskite light-emitting diodes （PeLEDs）， as the latest emerging display technology， have advantages such as high color purity， wide color gamut， simple processing technology， and low cost. PeLEDs are a research hotspot in the field of optoelectronic devices at home and abroad. However， it is necessary to use lead halide perovskites that are harmful to the environment in order to achieve high power conversion efficiency. Among them， tin halide perovskite is the most promising alternative， which has low exciton binding energy and good charge carrier mobility. Due to similar ionic radii and valence states， tin （Sn） can partially or completely replace toxic lead （Pb） to achieve low lead or non-toxic lead halide perovskites. Meanwhile， partial or complete replacement of Pb by Sn will result in new luminescent properties. Although significant progress has been made in improving the optoelectronic properties of Sn based halide perovskites， the parameters of the luminescent devices prepared from them are still lower than those of lead-based halide perovskites. This article aims to provide a detailed overview of the research progress and challenges faced in the synthesis， preparation， and optoelectronic properties of Sn based halide perovskites. The relationship between crystal structure and optoelectronic properties is explored. The research progress in the application of Sn based perovskites in electroluminescent devices are reviewed. The focus is on strategies adopted to improve the thin film properties of Sn based perovskite materials to enhance device performance. This review provides a reference for the synthesis， luminescent properties， and LEDs applications of tin based metal halide perovskites.关键词：metal halide perovskites;Sn based;electroluminescent devices;light-emitting diode （LED）92|103|0更新时间：2025-04-21
- 摘要：InAlGaAs/AlGaAs multiple quantum wells （MQWs） have attracted increasing attention in the near-infrared and visible light fields due to their wide spectral range， and have become an emerging research hotspot. This study uses metal organic chemical vapor deposition （MOCVD） growth technology to prepare InAlGaAs/AlGaAs multi quantum well materials. Based on the main factors and theoretical calculation methods that need to be considered when selecting the insertion layer （ISL） material， the influence of the insertion layer structure on the luminescence properties of quantum wells is explored. We designed and grew InAlGaAs quantum wells without an insertion layer， as well as InAlGaAs quantum wells with AlGaAs insertion layers of varying thicknesses and Al compositions. The experimental results show that the introduction of the insertion layer significantly improves the luminescence intensity of the quantum well. Although there are localized states in the sample itself， the presence of the insertion layer does not introduce more localized states， and the presence of the insertion layer does not change the carrier recombination mechanism in quantum wells. The research results provide important theoretical analysis and experimental data for the structural optimization and insertion layer technology of InAlGaAs quantum wells， indicating that the optical performance of InAlGaAs quantum wells can be significantly improved by designing the insertion layer reasonably.关键词：InAlGaAs multi quantum well;insertion layer;metal organic chemical vapor deposition（MOCVD）48|107|0更新时间：2025-04-21
- 摘要：The red phosphor NaGdMgTeO6∶xEu3+ （x = 0.1-1.0） was successfully prepared using the high-temperature solid-phase method. Comprehensive characterization of its structural， and photoluminescence properties was conducted using X-ray diffraction （XRD）， scanning electron microscopy （SEM）， diffuse reflectance spectroscopy （DR）， photoluminescence spectroscopy （PL）， and electroluminescence （EL） measurements. Under 397 nm UV excitation， NaGdMgTeO6∶Eu3+ exhibits characteristic emission of Eu3+. The optimal doping concentration of Eu3+ was found to be x = 0.5， beyond which higher concentrations result in concentration quenching. Temperature-dependent PL spectra were analyzed to investigate the thermal stability and potential application of NaGdMgTeO6∶0.5Eu3+ as a temperature sensor. Key parameters related to its temperature sensing performance were calculated. Additionally， the photoelectrical properties of LED devices fabricated with this phosphor were evaluated， demonstrating its promising application in solid-state lighting. Furthermore， the material showed potential for latent fingerprint detection， indicating its multifunctional nature. In summary， NaGdMgTeO6∶Eu3+ emerges as a versatile material with potential applications across various fields.关键词：NaGdMgTeO6;luminescence;LED;temperature sensing;latent fingerprint59|34|0更新时间：2025-04-21
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Synthesis and Coloring Properties of A Novel Garnet-type Green Ceramic Pigment Y3Ga3MgSiO12∶Cr3+ 增强出版
摘要：Novel green ceramic pigments Y3Ga3MgSiO12∶xCr3+ （x=0-0.2） were successfully synthesized via the conventional solid-state approach. The properties of the pigments were studied by XRD， FE-SEM， UV-Vis spectroscopy， XPS， and chromaticity analysis. The findings reveal that the trivalent chromium ions occupy the ［Ga1O6］ octahedral sites within the garnet lattice， and the relatively weak crystal field environment provided by the matrix endows the pigments with green characteristics. The samples prepared by calcination at 1 400 ℃ exhibit the most excellent performance in terms of phase purity， morphology， and color properties. The chromaticity values for the representative sample Y3Ga3MgSiO12∶0.05Cr3+ are L* = 81.16， a* = -12.53， and b* = 12.71， and the color remains stable after the stability test. Moreover， when glazed with Y3Ga3MgSiO12∶xCr3+ （x = 0-0.2） pigments， the smooth glaze surfaces exhibit vivid and saturated green tones， demonstrating their remarkable coloring capabilities and promising potential as a practical pigment for medium-temperature applications. This research underscores the vast application prospects of Y3Ga3MgSiO12∶Cr3+ as an innovative green ceramic pigment.关键词：Garnet;Green pigments;Cr3+ doping77|22|0更新时间：2025-04-21
Synthesis and Properties of Materials
- 摘要：Photonic crystal surface emitting laser （PCSEL） can achieve large-area coherent oscillation by utilizing band-edge resonance effects， making it a new type of semiconductor laser capable of high-brightness single-mode emission， including highly collimated beams， power scaling with area， and low divergence angles， which gives PCSEL great application prospects in the fields such as lidar and 3D sensing. This paper designs a square single-crystal lattice asymmetric conical air hole structure for the PCSEL. By increasing the duty cycle of the photonic crystal， the threshold difference between the fundamental mode and higher-order modes is enhanced， enabling high-power single-mode laser output over a large mode area. Experimental results show that the developed 940 nm PCSEL achieves an output power of 5.1 W under 10 μs wide pulse pumping， with a slope efficiency of 0.43 W/A， and its far-field light spot exhibits a single-lobe distribution with a 1° far-field divergence angle， with a linearly polarized characteristic and an 80% polarization. Furthermore， under 5 ns narrow pulse conditions， the output power reaches as high as 35 W. The development of this device can provide a good light source for laser radar systems.关键词：Photonic crystal surface emitting semiconductor laser（PCSEL）;high power;asymmetric cone shape83|29|0更新时间：2025-04-21
- 摘要：Electron extraction property is one of the important issues that limited the performance of perovskite solar cells （PSCs）. SnO2 electron transport layer fabricated with a chemical bath deposition method has been suc-cessful used in PSCs. However， it usually has a large number of oxygen vacancies at its surface， which would act as nonradiative recombination centers at the SnO2/perovskite buried interface. Herein， a SnCl4 and （NH4）2CrO4 bimolecularly passivated buried interface strategy is adopted in PSCs， and the device shows a power conversion efficiency of 23.71%. The hydrolysis of SnCl4 forms a layer of small SnO2 nanoparticles on the surface SnO2， resulting in a smooth surface. （NH4）2CrO4 acts as an oxidizer and forms a thin layer of p-type semiconductor Cr2O3 on n-type SnO2. Such p-n heterojunctions compensate the oxygen vacancies on SnO2 surface， which decreases the nonradiative recombination at the buried interface and hence increases the electron extraction efficiency. Meanwhile， the perovskite film deposited on the bimolecularly passivated SnO2 exhibits increased grain size， leading to decreased concentration of defects.关键词：perovskite solar cells;tin dioxide;defects;bimolecularly passivation99|64|0更新时间：2025-04-21
- 摘要：To overcome the limitations of symmetric uniform grating structures and enhance the coupling efficiency of on-chip light sources in silicon-based photonic integrated circuits （PICs）， this study proposes a high-efficiency progressive grating coupler based on a silicon-on-insulator platform. This design is specifically suited for vertical-cavity surface-emitting lasers （VCSELs） bonded to silicon photonic ICs， reducing the technical challenges associated with bonding angle alignment. The method involves simultaneous adjustments to the grating period and duty cycle， along with optimization of etching depth， to better align the diffracted field with the Gaussian beam profile by refining the Bragg condition. To compare performance， uniform grating couplers with fixed periods and duty cycles， as well as front-end progressive grating couplers with fixed periods and varying duty cycles， are also studied.Results validate the progressive grating superior performance， achieving coupling efficiencies of 54.62% （-2.63 dB） for the uniform grating， 60.18% （-2.21 dB） for the front-end progressive grating， and 64.55% （-1.90 dB） for the proposed progressive design. The optimized structure demonstrates an angular tolerance of 6°-21° for the incident light source， significantly easing fabrication challenges. The study confirms that the heterogeneous integration structure can achieve coupling efficiencies as high as 64.55% （-1.90 dB） without requiring a back reflector， while maintaining a wide angular tolerance. Experimental results further reveal high coupling efficiency across the 1 500-1 600 nm wavelength range and consistent performance across varying fiber incident angles， highlighting the design’s practicality and robustness for real-world applications.关键词：silicon photonic integrated;mode matching;incident angle tolerance;coupling efficiency;grating coupler66|38|0更新时间：2025-04-21
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