Air sterilizers have gained widespread market adoption, but their functionality remains limited to singular purposes such as disinfection or odor removal.The MASSPHOTON ’ s Q6060-D UV-C air sterilizer utilizes solid-state semiconductor technology with UV-C LEDs emitting 260-280nm single-wavelength ultraviolet light, which can inactivate a broad spectrum of microorganisms by blocking DNA and RNA replication. Installed on the ceiling of meeting rooms, garbage rooms, and corridors in a normally operating shopping mall in Hong Kong, the MASSPHOTON ’ s Q6060-D UV-C air sterilizer achieved a sterilization rate of 70.8% in the garbage room and 61.62% in the meeting room. Although during the odor removal test, wall painting activities in a rented shop significantly increased TVOC levels, the use of the MASSPHOTON air sterilizer reduced the initial TVOC level from 10.00 mg/m³ to 3.53 mg/m³ within 2 hours. In a simulated test conducted in a 112 m³ room, after four cigarettes were completely burned, the MASSPHOTON’s Q6060-D UV-C air sterilizer was immediately activated. After 4 hours, the PM2.5 concentration was effectively reduced by 61.1%, and the TVOC concentration was reduced by 98.2%. Using 10% ammonia solution as a volatile ammonia gas test, the ammonia removal rate reached 99.9% within 90 minutes. Based on all experimental results, it can be concluded that the MASSPHOTON ’ s Q6060-D UV-C air sterilizer can effectively reduce the number of natural bacteria in the air while adsorbing particulate matter in the environment, decomposing odor molecules, maintaining air cleanliness and freshness, preventing the spread of respiratory diseases, and protecting vulnerable populations.

ABSTRACT

Achieving low resistance ohmic connections is one of the significant factors in improving the performance of optoelectric and semiconductor devices. In this work, we examined the decrease in specific contact resistance (ρc) after high-temperature annealing and vanadium thickness variation on an n-type AlGaN epitaxial layer with a high aluminum concentration (75%). To measure it, we prepared rectangular transmission line model electrodes and measured the specific contact resistance at annealing temperatures ranging between 800 and 950 ○C. The results showed that the minimum specific contact resistance achieved was 4.12 × 10−2 Ω cm2 at an annealing temperature of 850 ○C, which was two times lower compared to that of surface contact mode. It is also demonstrated how the contact resistance of the epitaxial n-type AlGaN layer varies as the vanadium thickness changes from 2 to 15 nm.

© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International (CC BY-NC-ND) license (https://creativecommons.org/licenses/by-nc-nd/4.0/). https://doi.org/10.1063/5.0210229

The spread of infectious diseases within hospitals is notably exacerbated by cross-contamination through small medical devices such as mobile phones, blood pressure monitors, and glucose meters. However, current disinfection equipment has significant limitations: it is not only difficult to adapt to medical devices of various sizes, but also incapable of subjecting delicate electronic equipment to high-temperature disinfection processes. This situation severely hampers the effective implementation of infection prevention and control measures in hospitals. This study addresses the aforementioned challenges by designing a surface disinfection cabinet for small medical devices, utilizing UV-C LED technology as its core component. Through simulation modeling and practical testing, the disinfection efficacy of this technology on devices such as mobile phones, PDAs, and blood pressure monitors was evaluated. Collected three mobile phones, one tablet, two device remotes, and one packaging box from laboratory personnel, totaling seven small items of different materials and specifications. The colony counts before and after using the device were collected and tested, with each test repeated more than three times. The results indicate a significant reduction in the number of bacterial colonies on the sample surfaces before and after disinfection, with an average sterilization rate of 99.4%. The growth of natural bacteria in the culture dishes was less than 1 CFU/cm², meeting the requirement of a reduction in natural bacterial count by more than 1.00 log as stipulated by GB27952-2020 "General Requirements for Disinfectants on Common Object Surfaces". Additionally, tests confirmed that the device does not produce ozone and poses no risk of ultraviolet leakage in the laboratory within the factory premises, allowing for continuous use in rooms with people present.

GaN power high electron mobility transistors (HEMTs) with a breakdown voltage (BV) exceeding 2500 V at IDSS leakage of 1 μA mm−1 grown by plasma-assisted MBE (PA-MBE) on sapphire was demonstrated with a single field plate structure. Subdividing the 70 nm GaN channel into 12 layers has been shown to exhibit fewer defect states and reduced pore defects, thereby benefiting the BV. The single gate field plate technique helps to simplify the peak electric field condition and also contributes to the high BV. These advantages underscore the potential of the PA-MBE-grown GaN power HEMT for high-power electronic applications.

We report on a GaN power HEMT with a breakdown voltage exceeding 800 V, grown by MBE on sapphire. The high breakdown voltage, surpassing 800 V, is achieved through the use of an ultra-thin AlN buffer layer grown by MBE and the implementation of a single-level gate field plate technique. The MBE technique facilitates the growth of a dopant-free buffer layer and pseudomorphic epilayers, which is advantageous for the high reliability of GaN power HEMTs. Additionally, the single-level gate field plate technique aids in reducing the overall fabrication cost and also enhances the reliability of GaN power HEMTs. These merits highlight the potential of the reported GaN power HEMT for applications in high-power electronics.

Deep UV LED package is a hotspot of growing concern for research scholars, it is through the LED semiconductor light-emitting devices emit UVC band ultraviolet (typical wavelength 260 ~ 280nm), is a new type of healthy artificial light source, compared with the traditional UV light source mercury lamps, the deep UV LED has a wavelength of accurate and controllable, green, and so on many advantages. Due to the high-energy deep UV radiation capability, it has a strong bactericidal and inactivation effect on bacteria, viruses and other microorganisms. In recent years, with the continuous progress of deep packaging technology, the optical efficiency and reliability of deep UV LEDs have been significantly improved. This paper summarizes the key technologies of deep-ultraviolet packaging, the performance of deep-ultraviolet LEDs and the application of deep-ultraviolet LEDs; through the understanding of the packaging materials, packaging structure, packaging process and so on to improve the performance of deep-ultraviolet LEDs, so that it is better to apply to the market, which can be seen that the deep-ultraviolet LEDs have a great prospect for development.

To address the problem of low efficiency of AlGaN-based UV LED chips, this study developed a type of solid–liquid packaged UV LED chip and analyzed its light output efficiency under different parameters. The light output efficiency of UV LED chips with and without solid–liquid encapsulation were analyzed using different reflective materials inside the chips. It was found that Au, Ag, and total-absorption reflective materials could not improve the light-output efficiency of UV LED liquid packaging. In addition, Al reflective materials and total reflection photonic crystals can improve the light output efficiency of UV LED liquid packaging, with the highest efficiency increase reaching over 74%. The light output efficiencies of liquid packaging with quartz cover sheets of different thicknesses were analyzed; the results revealed that the thinner the quartz cover sheet, the higher the efficiency; Under the same conditions, the efficiency improvement of UV LED surface-mount beads is not significant with different thicknesses of quartz cover sheets; Under the same thickness of quartz cover, Al reflective material and total reflection photonic crystal can improve the light output efficiency of UV LED liquid packaging.

This study systematically evaluated the sterilization performance and reliability of a UV-C LED water disinfection module based on 270–280 nm gallium nitride (GaN) high-power chips under various configurations, structural parameters, and pressure conditions. The experiment first analyzed the impact of the number of dual-chip UV-C LED beads on irradiation intensity and sterilization efficacy. At a flow rate of 9 L/min, configurations with 5-series-2-parallel (10 beads), 4-series-2-parallel (8 beads), and 3-series-2-parallel (6 beads) yielded irradiation intensities of 377 µW/cm², 320 µW/cm², and 273 µW/cm², respectively. The results demonstrated that, even with a 40%reduction in the number of beads and a 27.5% decrease in irradiation intensity, the system achieved a 99.999% inactivation rate for Escherichia coli.To further optimize system performance and cost, several structural improvements were implemented: replacing the aluminum substrate with a copper substrate reduced the optical power attenuation rate from 54% to 42%; increasing the quartz tube diameter from 6 mm to 16 mm effectively extended the water-UV contact time; and optimizing the aperture design of high-reflectivity materials improved light utilization efficiency. Based on these structural enhancements, tests were conducted using single-chip UV-C LED bead configurations (10, 8, and 6 beads), resulting in irradiation intensities of 305 µW/cm², 250 µW/cm², and 210 µW/cm², respectively, which were 19%–23% lower than those of equivalent dual-chip configurations. Nevertheless, the sterilization rate remained stable at 99.999%.Sealing and pressure resistance tests revealed that the module, sealed with food-grade silicone, achieved the designed flow rate of 9 L/min at an inlet pressure of 0.12 MPa, with a maximum pressure tolerance of 0.45 MPa. No leakage was observed during long-term operation, indicating excellent mechanical sealing and operational stability. This study provides critical experimental evidence and design references for developing efficient, cost-effective, and reliable UV-C LED water disinfection systems, facilitating their application in practical water treatment scenarios.

This study systematically evaluated the sterilization performance and reliability of a UV-C LED water disinfection module based on 270–280 nm gallium nitride (GaN) high-power chips under various configurations, structural parameters, and pressure conditions. The experiment first analyzed the impact of the number of dual-chip UV-C LED beads on irradiation intensity and sterilization efficacy. At a flow rate of 9 L/min, configurations with 5-series-2-parallel (10 beads), 4-series-2-parallel (8 beads), and 3-series-2-parallel (6 beads) yielded irradiation intensities of 377 µW/cm², 320 µW/cm², and 273 µW/cm², respectively. The results demonstrated that, even with a 40%reduction in the number of beads and a 27.5% decrease in irradiation intensity, the system achieved a 99.999% inactivation rate for Escherichia coli.To further optimize system performance and cost, several structural improvements were implemented: replacing the aluminum substrate with a copper substrate reduced the optical power attenuation rate from 54% to 42%; increasing the quartz tube diameter from 6 mm to 16 mm effectively extended the water-UV contact time; and optimizing the aperture design of high-reflectivity materials improved light utilization efficiency. Based on these structural enhancements, tests were conducted using single-chip UV-C LED bead configurations (10, 8, and 6 beads), resulting in irradiation intensities of 305 µW/cm², 250 µW/cm², and 210 µW/cm², respectively, which were 19%–23% lower than those of equivalent dual-chip configurations. Nevertheless, the sterilization rate remained stable at 99.999%.Sealing and pressure resistance tests revealed that the module, sealed with food-grade silicone, achieved the designed flow rate of 9 L/min at an inlet pressure of 0.12 MPa, with a maximum pressure tolerance of 0.45 MPa. No leakage was observed during long-term operation, indicating excellent mechanical sealing and operational stability. This study provides critical experimental evidence and design references for developing efficient, cost-effective, and reliable UV-C LED water disinfection systems, facilitating their application in practical water treatment scenarios.

This study systematically investigates the performance optimization of UV-C LED water disinfection modules, focusing on the effects of heat dissipation materials, driving current, and optical structure design on sterilization efficiency. The results demonstrate that copper substrates significantly reduce the light power attenuation rate of UV-C LEDs compared to aluminum substrates (41.90% vs. 53.94%), thereby extending the operational lifespan of the device. In flow-through water disinfection experiments, increasing the driving current (from 100 mA to 200 mA) markedly enhances inactivation efficiency, achieving an Escherichia coli inactivation rate of >99.999% at 200 mA, which meets drinking water disinfection standards. Furthermore, by optimizing the optical design, the number of UV-C LED beads was reduced from six to four, and individual perforations for each bead were employed to enhance ultraviolet reflection. This approach maintained a high sterilization rate of 99.999% while reducing costs by 33%. This study provides critical theoretical foundations and engineering references for the design of efficient, cost-effective, and long-lasting UV-C LED water disinfection systems.

This work reports GaN power high-electron-mobility transistors (HEMTs) that achieve a breakdown voltage (BV) exceeding 2400 V (defined at IDSS <1 μA mm−1) through the implementation of a single gate field plate (FP). This design establishes a simplified yet optimized electric field profile, which is key to achieving a high BV while maintaining favorable dynamic performance. The dynamic ON-resistance (Ron) remains as low as 106% after OFF-state VDS stress at 600 V. The combination of high BV and robust dynamic characteristics demonstrates that the single gate FP technique is a promising approach for the mass production of high-performance GaN power HEMTs, offering the potential for reduced process complexity and cost without compromising device performance.

The strategic selection of lens geometry—spherical versus plane—decisively shapes the opto-thermal performance boundary of deep ultraviolet light-emitting diodes (DUV-LEDs), thereby governing their efficacy in application-specific photochemical processes. This study demonstrates that spherical lenses, by virtue of their superior light-collecting geometry, significantly enhance optical extraction efficiency and thermal management performance compared to conventional plane lenses. These engineered performance characteristics translate directly into divergent functional outcomes: spherical lenses enable rapid, high-intensity processing, while plane lenses are better suited for controlled, sustained operation. The findings establish a fundamental principle for DUV-LED packaging design: lens geometry can be tailored to optimize efficiency for distinct photochemical tasks, providing a clear pathway from device engineering to application-driven performance.

This study systematically investigated the mechanisms underlying the effects of UV-C LED irradiation on the preservation of fresh fruits. High-power 270–280 nm gallium nitride (GaN)-based UV-C LED chips were employed, with device performance enhanced through optimized heat dissipation structures and a matrix arrangement design. Experimental results demonstrated that, under ambient conditions (22–27°C), a 75% duty cycle UV-C irradiation (45 s on/15 s off) achieved the most effective suppression of mold growth on apple slices and raspberries, completely inhibiting mold proliferation. The 25% duty cycle (15 s on/45 s off) provided a better balance between antibacterial efficacy and maintaining fruit freshness. In a 4°C refrigerated environment, the 25% irradiation mode (15 s on/45 s off, 40 cm distance) reduced the spoilage rate of raspberries from 100% to 20%. For strawberries, while UV-C irradiation completely suppressed mold growth, it induced significant oxidative damage (44.4% of fruits exhibited water-soaked spots) and a higher weight loss rate (14% compared to 6% in the control group). These findings confirm that UV-C irradiation effectively controls postharvest microbial spoilage in fruits, but optimization of irradiation parameters is necessary to balance antibacterial efficacy with fruit quality preservation.

Microwave acoustic components have higher quality factors and less crosstalk than electromagnetic components. Efficient modulation of acoustic devices is essential for building large-scale multifunctional acoustic circuits. Here, we demonstrate a thermo-acoustic phase modulator based on a Y36-cut LiNbO3 (LN) thin-film platform. The proposed structure integrates a 460 MHz SH0 mode acoustic delay line and an on-chip microheater for locally changing the temperature and thus controlling the phase of the ADL. Using this approach, we achieve a phase change of more than 281° at a heating power of 20 mW, and a modulation ability of 17 °/mW in the linear modulation range, which is a 6.5 times improvement over previously reported bulk-LN platforms. Our thermo-acoustic modulators enable reconfigurable acoustic signal processing for next-generation wireless communication and microwave systems.

A wavelength-scale focusing transducer based on suspended Aluminum nitride (AlN) piezoelectric thin film are designed, simulated and fabricated. The one port device was simulated and analyzed to verify the device focusing perfor-mance. Two-port acoustic delay line under different electrical configuration was simulated, fabricated and analyzed to evaluate the electro-acoustic transduction capability of the transducer. According to the simulation and measurenment results, the transducer can produce the expected focused gaussian lamb beam with a beam waist of 5 µm which is half of the wavelength. The insertion loss of 32.16 dB at 824.13 MHz proves the efficient electromechanical transduction capability of the transducer. The transducer is the potential component in phononic integrated circuits (PnICs).

The aim of this study was to evaluate the efficacy of a novel air sterilization system on airborne microorganisms in both lab envi-ronment and office environment. Here we used a UV-C LED based technique to continuously purify the air. It was observed that in lab testing environment, the disinfection rate of the UV-C LED system is 99.94% against staphylococci albus (8032) within a 20 m3 space in 2 hours, while 99.6%, 99.02% and 98.65% against natural microorganisms in 2 hours within 100 m3, 150 m3 and 210 m3 space respectively. Additionally, for a 5-day onsite testing conducted in normally operating offices, the results show a disinfection rate up to 92% against natural airborne microorganisms. The results also show zero ozone emission from the UV-C LED based air sterilization de-vices. This study demonstrates a promising role for this UV-C LED based novel technology in infection control and prevention by de-creasing the spread of airborne pathogens effectively and efficiently without introducing hazardous mercury or any chemicals.

Since the junction temperature is a critical factor determining the lifetime and reliability of LEDs, effective thermal management is essential to prevent premature failure. This study uses COMSOL Multiphysics® to simulate a 10 W multi-chip COB LED package, focusing on the role of thermally conductive adhesive films. Results show that junction temperature is more sensitive to film thickness than to thermal conductivity. Reducing thickness from 0.6 mm to 0.1 mm gradually improves cooling, with diminishing returns below 0.1 mm. Similarly, thermal conductivity above 5 W/m·K offers limited improvement. Dense chip layouts intensify the film’s influence. Optimizing these parameters effectively reduces local overheating and enhances dissipation. This study provides practical guidelines for enhancing the long-term reliability of high-density LED packaging by strategically optimizing adhesive film parameters to mitigate thermal-induced degradation.

Keywords: multi-chip COB LED; thermal management; finite element simulation; adhesive film

Since the junction temperature is a critical factor determining the lifetime and reliability of LEDs, effective thermal management is essential to prevent premature failure. This study uses COMSOL Multiphysics® to simulate a 10 W multi-chip COB LED package, focusing on the role of thermally conductive adhesive films. Results show that junction temperature is more sensitive to film thickness than to thermal conductivity. Reducing thickness from 0.6 mm to 0.1 mm gradually improves cooling, with diminishing returns below 0.1 mm. Similarly, thermal conductivity above 5 W/m·K offers limited improvement. Dense chip layouts intensify the film’s influence. Optimizing these parameters effectively reduces local overheating and enhances dissipation. This study provides practical guidelines for enhancing the long-term reliability of high-density LED packaging by strategically optimizing adhesive film parameters to mitigate thermal-induced degradation.

Keywords: multi-chip COB LED; thermal management; finite element simulation; adhesive film

ABSTRACT

Achieving low resistance ohmic connections is one of the significant factors in improving the performance of optoelectric and semiconductor devices. In this work, we examined the decrease in specific contact resistance (ρc) after high-temperature annealing and vanadium thickness variation on an n-type AlGaN epitaxial layer with a high aluminum concentration (75%). To measure it, we prepared rectangular transmission line model electrodes and measured the specific contact resistance at annealing temperatures ranging between 800 and 950 ○C. The results showed that the minimum specific contact resistance achieved was 4.12 × 10−2 Ω cm2 at an annealing temperature of 850 ○C, which was two times lower compared to that of surface contact mode. It is also demonstrated how the contact resistance of the epitaxial n-type AlGaN layer varies as the vanadium thickness changes from 2 to 15 nm.

© 2024 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International (CC BY-NC-ND) license (https://creativecommons.org/licenses/by-nc-nd/4.0/). https://doi.org/10.1063/5.0210229

This study systematically investigates the performance optimization of UV-C LED water disinfection modules, focusing on the effects of heat dissipation materials, driving current, and optical structure design on sterilization efficiency. The results demonstrate that copper substrates significantly reduce the light power attenuation rate of UV-C LEDs compared to aluminum substrates (41.90% vs. 53.94%), thereby extending the operational lifespan of the device. In flow-through water disinfection experiments, increasing the driving current (from 100 mA to 200 mA) markedly enhances inactivation efficiency, achieving an Escherichia coli inactivation rate of >99.999% at 200 mA, which meets drinking water disinfection standards. Furthermore, by optimizing the optical design, the number of UV-C LED beads was reduced from six to four, and individual perforations for each bead were employed to enhance ultraviolet reflection. This approach maintained a high sterilization rate of 99.999% while reducing costs by 33%. This study provides critical theoretical foundations and engineering references for the design of efficient, cost-effective, and long-lasting UV-C LED water disinfection systems.

GaN power high electron mobility transistors (HEMTs) with a breakdown voltage (BV) exceeding 2500 V at IDSS leakage of 1 μA mm−1 grown by plasma-assisted MBE (PA-MBE) on sapphire was demonstrated with a single field plate structure. Subdividing the 70 nm GaN channel into 12 layers has been shown to exhibit fewer defect states and reduced pore defects, thereby benefiting the BV. The single gate field plate technique helps to simplify the peak electric field condition and also contributes to the high BV. These advantages underscore the potential of the PA-MBE-grown GaN power HEMT for high-power electronic applications.

We report on a GaN power HEMT with a breakdown voltage exceeding 800 V, grown by MBE on sapphire. The high breakdown voltage, surpassing 800 V, is achieved through the use of an ultra-thin AlN buffer layer grown by MBE and the implementation of a single-level gate field plate technique. The MBE technique facilitates the growth of a dopant-free buffer layer and pseudomorphic epilayers, which is advantageous for the high reliability of GaN power HEMTs. Additionally, the single-level gate field plate technique aids in reducing the overall fabrication cost and also enhances the reliability of GaN power HEMTs. These merits highlight the potential of the reported GaN power HEMT for applications in high-power electronics.

Deep UV LED package is a hotspot of growing concern for research scholars, it is through the LED semiconductor light-emitting devices emit UVC band ultraviolet (typical wavelength 260 ~ 280nm), is a new type of healthy artificial light source, compared with the traditional UV light source mercury lamps, the deep UV LED has a wavelength of accurate and controllable, green, and so on many advantages. Due to the high-energy deep UV radiation capability, it has a strong bactericidal and inactivation effect on bacteria, viruses and other microorganisms. In recent years, with the continuous progress of deep packaging technology, the optical efficiency and reliability of deep UV LEDs have been significantly improved. This paper summarizes the key technologies of deep-ultraviolet packaging, the performance of deep-ultraviolet LEDs and the application of deep-ultraviolet LEDs; through the understanding of the packaging materials, packaging structure, packaging process and so on to improve the performance of deep-ultraviolet LEDs, so that it is better to apply to the market, which can be seen that the deep-ultraviolet LEDs have a great prospect for development.

To address the problem of low efficiency of AlGaN-based UV LED chips, this study developed a type of solid–liquid packaged UV LED chip and analyzed its light output efficiency under different parameters. The light output efficiency of UV LED chips with and without solid–liquid encapsulation were analyzed using different reflective materials inside the chips. It was found that Au, Ag, and total-absorption reflective materials could not improve the light-output efficiency of UV LED liquid packaging. In addition, Al reflective materials and total reflection photonic crystals can improve the light output efficiency of UV LED liquid packaging, with the highest efficiency increase reaching over 74%. The light output efficiencies of liquid packaging with quartz cover sheets of different thicknesses were analyzed; the results revealed that the thinner the quartz cover sheet, the higher the efficiency; Under the same conditions, the efficiency improvement of UV LED surface-mount beads is not significant with different thicknesses of quartz cover sheets; Under the same thickness of quartz cover, Al reflective material and total reflection photonic crystal can improve the light output efficiency of UV LED liquid packaging.

This study systematically evaluated the sterilization performance and reliability of a UV-C LED water disinfection module based on 270–280 nm gallium nitride (GaN) high-power chips under various configurations, structural parameters, and pressure conditions. The experiment first analyzed the impact of the number of dual-chip UV-C LED beads on irradiation intensity and sterilization efficacy. At a flow rate of 9 L/min, configurations with 5-series-2-parallel (10 beads), 4-series-2-parallel (8 beads), and 3-series-2-parallel (6 beads) yielded irradiation intensities of 377 µW/cm², 320 µW/cm², and 273 µW/cm², respectively. The results demonstrated that, even with a 40%reduction in the number of beads and a 27.5% decrease in irradiation intensity, the system achieved a 99.999% inactivation rate for Escherichia coli.To further optimize system performance and cost, several structural improvements were implemented: replacing the aluminum substrate with a copper substrate reduced the optical power attenuation rate from 54% to 42%; increasing the quartz tube diameter from 6 mm to 16 mm effectively extended the water-UV contact time; and optimizing the aperture design of high-reflectivity materials improved light utilization efficiency. Based on these structural enhancements, tests were conducted using single-chip UV-C LED bead configurations (10, 8, and 6 beads), resulting in irradiation intensities of 305 µW/cm², 250 µW/cm², and 210 µW/cm², respectively, which were 19%–23% lower than those of equivalent dual-chip configurations. Nevertheless, the sterilization rate remained stable at 99.999%.Sealing and pressure resistance tests revealed that the module, sealed with food-grade silicone, achieved the designed flow rate of 9 L/min at an inlet pressure of 0.12 MPa, with a maximum pressure tolerance of 0.45 MPa. No leakage was observed during long-term operation, indicating excellent mechanical sealing and operational stability. This study provides critical experimental evidence and design references for developing efficient, cost-effective, and reliable UV-C LED water disinfection systems, facilitating their application in practical water treatment scenarios.

This work reports GaN power high-electron-mobility transistors (HEMTs) that achieve a breakdown voltage (BV) exceeding 2400 V (defined at IDSS <1 μA mm−1) through the implementation of a single gate field plate (FP). This design establishes a simplified yet optimized electric field profile, which is key to achieving a high BV while maintaining favorable dynamic performance. The dynamic ON-resistance (Ron) remains as low as 106% after OFF-state VDS stress at 600 V. The combination of high BV and robust dynamic characteristics demonstrates that the single gate FP technique is a promising approach for the mass production of high-performance GaN power HEMTs, offering the potential for reduced process complexity and cost without compromising device performance.

The strategic selection of lens geometry—spherical versus plane—decisively shapes the opto-thermal performance boundary of deep ultraviolet light-emitting diodes (DUV-LEDs), thereby governing their efficacy in application-specific photochemical processes. This study demonstrates that spherical lenses, by virtue of their superior light-collecting geometry, significantly enhance optical extraction efficiency and thermal management performance compared to conventional plane lenses. These engineered performance characteristics translate directly into divergent functional outcomes: spherical lenses enable rapid, high-intensity processing, while plane lenses are better suited for controlled, sustained operation. The findings establish a fundamental principle for DUV-LED packaging design: lens geometry can be tailored to optimize efficiency for distinct photochemical tasks, providing a clear pathway from device engineering to application-driven performance.

Microwave acoustic components have higher quality factors and less crosstalk than electromagnetic components. Efficient modulation of acoustic devices is essential for building large-scale multifunctional acoustic circuits. Here, we demonstrate a thermo-acoustic phase modulator based on a Y36-cut LiNbO3 (LN) thin-film platform. The proposed structure integrates a 460 MHz SH0 mode acoustic delay line and an on-chip microheater for locally changing the temperature and thus controlling the phase of the ADL. Using this approach, we achieve a phase change of more than 281° at a heating power of 20 mW, and a modulation ability of 17 °/mW in the linear modulation range, which is a 6.5 times improvement over previously reported bulk-LN platforms. Our thermo-acoustic modulators enable reconfigurable acoustic signal processing for next-generation wireless communication and microwave systems.

A wavelength-scale focusing transducer based on suspended Aluminum nitride (AlN) piezoelectric thin film are designed, simulated and fabricated. The one port device was simulated and analyzed to verify the device focusing perfor-mance. Two-port acoustic delay line under different electrical configuration was simulated, fabricated and analyzed to evaluate the electro-acoustic transduction capability of the transducer. According to the simulation and measurenment results, the transducer can produce the expected focused gaussian lamb beam with a beam waist of 5 µm which is half of the wavelength. The insertion loss of 32.16 dB at 824.13 MHz proves the efficient electromechanical transduction capability of the transducer. The transducer is the potential component in phononic integrated circuits (PnICs).

This study systematically evaluated the sterilization performance and reliability of a UV-C LED water disinfection module based on 270–280 nm gallium nitride (GaN) high-power chips under various configurations, structural parameters, and pressure conditions. The experiment first analyzed the impact of the number of dual-chip UV-C LED beads on irradiation intensity and sterilization efficacy. At a flow rate of 9 L/min, configurations with 5-series-2-parallel (10 beads), 4-series-2-parallel (8 beads), and 3-series-2-parallel (6 beads) yielded irradiation intensities of 377 µW/cm², 320 µW/cm², and 273 µW/cm², respectively. The results demonstrated that, even with a 40%reduction in the number of beads and a 27.5% decrease in irradiation intensity, the system achieved a 99.999% inactivation rate for Escherichia coli.To further optimize system performance and cost, several structural improvements were implemented: replacing the aluminum substrate with a copper substrate reduced the optical power attenuation rate from 54% to 42%; increasing the quartz tube diameter from 6 mm to 16 mm effectively extended the water-UV contact time; and optimizing the aperture design of high-reflectivity materials improved light utilization efficiency. Based on these structural enhancements, tests were conducted using single-chip UV-C LED bead configurations (10, 8, and 6 beads), resulting in irradiation intensities of 305 µW/cm², 250 µW/cm², and 210 µW/cm², respectively, which were 19%–23% lower than those of equivalent dual-chip configurations. Nevertheless, the sterilization rate remained stable at 99.999%.Sealing and pressure resistance tests revealed that the module, sealed with food-grade silicone, achieved the designed flow rate of 9 L/min at an inlet pressure of 0.12 MPa, with a maximum pressure tolerance of 0.45 MPa. No leakage was observed during long-term operation, indicating excellent mechanical sealing and operational stability. This study provides critical experimental evidence and design references for developing efficient, cost-effective, and reliable UV-C LED water disinfection systems, facilitating their application in practical water treatment scenarios.

This study systematically investigates the performance optimization of UV-C LED water disinfection modules, focusing on the effects of heat dissipation materials, driving current, and optical structure design on sterilization efficiency. The results demonstrate that copper substrates significantly reduce the light power attenuation rate of UV-C LEDs compared to aluminum substrates (41.90% vs. 53.94%), thereby extending the operational lifespan of the device. In flow-through water disinfection experiments, increasing the driving current (from 100 mA to 200 mA) markedly enhances inactivation efficiency, achieving an Escherichia coli inactivation rate of >99.999% at 200 mA, which meets drinking water disinfection standards. Furthermore, by optimizing the optical design, the number of UV-C LED beads was reduced from six to four, and individual perforations for each bead were employed to enhance ultraviolet reflection. This approach maintained a high sterilization rate of 99.999% while reducing costs by 33%. This study provides critical theoretical foundations and engineering references for the design of efficient, cost-effective, and long-lasting UV-C LED water disinfection systems.

The aim of this study was to evaluate the efficacy of a novel air sterilization system on airborne microorganisms in both lab envi-ronment and office environment. Here we used a UV-C LED based technique to continuously purify the air. It was observed that in lab testing environment, the disinfection rate of the UV-C LED system is 99.94% against staphylococci albus (8032) within a 20 m3 space in 2 hours, while 99.6%, 99.02% and 98.65% against natural microorganisms in 2 hours within 100 m3, 150 m3 and 210 m3 space respectively. Additionally, for a 5-day onsite testing conducted in normally operating offices, the results show a disinfection rate up to 92% against natural airborne microorganisms. The results also show zero ozone emission from the UV-C LED based air sterilization de-vices. This study demonstrates a promising role for this UV-C LED based novel technology in infection control and prevention by de-creasing the spread of airborne pathogens effectively and efficiently without introducing hazardous mercury or any chemicals.

Air sterilizers have gained widespread market adoption, but their functionality remains limited to singular purposes such as disinfection or odor removal.The MASSPHOTON ’ s Q6060-D UV-C air sterilizer utilizes solid-state semiconductor technology with UV-C LEDs emitting 260-280nm single-wavelength ultraviolet light, which can inactivate a broad spectrum of microorganisms by blocking DNA and RNA replication. Installed on the ceiling of meeting rooms, garbage rooms, and corridors in a normally operating shopping mall in Hong Kong, the MASSPHOTON ’ s Q6060-D UV-C air sterilizer achieved a sterilization rate of 70.8% in the garbage room and 61.62% in the meeting room. Although during the odor removal test, wall painting activities in a rented shop significantly increased TVOC levels, the use of the MASSPHOTON air sterilizer reduced the initial TVOC level from 10.00 mg/m³ to 3.53 mg/m³ within 2 hours. In a simulated test conducted in a 112 m³ room, after four cigarettes were completely burned, the MASSPHOTON’s Q6060-D UV-C air sterilizer was immediately activated. After 4 hours, the PM2.5 concentration was effectively reduced by 61.1%, and the TVOC concentration was reduced by 98.2%. Using 10% ammonia solution as a volatile ammonia gas test, the ammonia removal rate reached 99.9% within 90 minutes. Based on all experimental results, it can be concluded that the MASSPHOTON ’ s Q6060-D UV-C air sterilizer can effectively reduce the number of natural bacteria in the air while adsorbing particulate matter in the environment, decomposing odor molecules, maintaining air cleanliness and freshness, preventing the spread of respiratory diseases, and protecting vulnerable populations.

This study systematically investigated the mechanisms underlying the effects of UV-C LED irradiation on the preservation of fresh fruits. High-power 270–280 nm gallium nitride (GaN)-based UV-C LED chips were employed, with device performance enhanced through optimized heat dissipation structures and a matrix arrangement design. Experimental results demonstrated that, under ambient conditions (22–27°C), a 75% duty cycle UV-C irradiation (45 s on/15 s off) achieved the most effective suppression of mold growth on apple slices and raspberries, completely inhibiting mold proliferation. The 25% duty cycle (15 s on/45 s off) provided a better balance between antibacterial efficacy and maintaining fruit freshness. In a 4°C refrigerated environment, the 25% irradiation mode (15 s on/45 s off, 40 cm distance) reduced the spoilage rate of raspberries from 100% to 20%. For strawberries, while UV-C irradiation completely suppressed mold growth, it induced significant oxidative damage (44.4% of fruits exhibited water-soaked spots) and a higher weight loss rate (14% compared to 6% in the control group). These findings confirm that UV-C irradiation effectively controls postharvest microbial spoilage in fruits, but optimization of irradiation parameters is necessary to balance antibacterial efficacy with fruit quality preservation.

The spread of infectious diseases within hospitals is notably exacerbated by cross-contamination through small medical devices such as mobile phones, blood pressure monitors, and glucose meters. However, current disinfection equipment has significant limitations: it is not only difficult to adapt to medical devices of various sizes, but also incapable of subjecting delicate electronic equipment to high-temperature disinfection processes. This situation severely hampers the effective implementation of infection prevention and control measures in hospitals. This study addresses the aforementioned challenges by designing a surface disinfection cabinet for small medical devices, utilizing UV-C LED technology as its core component. Through simulation modeling and practical testing, the disinfection efficacy of this technology on devices such as mobile phones, PDAs, and blood pressure monitors was evaluated. Collected three mobile phones, one tablet, two device remotes, and one packaging box from laboratory personnel, totaling seven small items of different materials and specifications. The colony counts before and after using the device were collected and tested, with each test repeated more than three times. The results indicate a significant reduction in the number of bacterial colonies on the sample surfaces before and after disinfection, with an average sterilization rate of 99.4%. The growth of natural bacteria in the culture dishes was less than 1 CFU/cm², meeting the requirement of a reduction in natural bacterial count by more than 1.00 log as stipulated by GB27952-2020 "General Requirements for Disinfectants on Common Object Surfaces". Additionally, tests confirmed that the device does not produce ozone and poses no risk of ultraviolet leakage in the laboratory within the factory premises, allowing for continuous use in rooms with people present.