The low modulation bandwidth of deep-ultraviolet(UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth Ⅲ-nitride microlight-...The low modulation bandwidth of deep-ultraviolet(UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth Ⅲ-nitride microlight-emitting diodes(μLEDs) emitting in the UV-C region and their applications in deep-UV communication systems. The fabricated UV-C μLEDs with 566 μm2 emission area produce an optical power of 196 μW at the 3400 A∕cm2 current density. The measured 3 dB modulation bandwidth of these μLEDs initially increases linearly with the driving current density and then saturates as 438 MHz at a current density of 71 A∕cm2, which is limited by the cutoff frequency of the commercial avalanche photodiode used for the measurement. A deep-UV communication system is further demonstrated. By using the UV-C μLED, up to 800 Mbps and 1.1 Gbps data transmission rates at bit error ratio of 3.8 × 10-3 are achieved assuming on-off keying and orthogonal frequency-division multiplexing modulation schemes, respectively.展开更多
240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated.Then,the external quantum efficiency(EQE)and light extraction efficiency(LEE)are systematically investigated by comparing size and edge ef...240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated.Then,the external quantum efficiency(EQE)and light extraction efficiency(LEE)are systematically investigated by comparing size and edge effects.Here,it is revealed that the peak optical output power increases by 81.83%with the size shrinking from 50.0 to 25.0μm.Thereinto,the LEE increases by 26.21%and the LEE enhancement mainly comes from the sidewall light extraction.Most notably,transversemagnetic(TM)mode light intensifies faster as the size shrinks due to the tilted mesa side-wall and Al reflector design.However,when it turns to 12.5μm sized micro-LEDs,the output power is lower than 25.0μm sized ones.The underlying mechanism is that even though protected by SiO2 passivation,the edge effect which leads to current leakage and Shockley-Read-Hall(SRH)recombination deteriorates rapidly with the size further shrinking.Moreover,the ratio of the p-contact area to mesa area is much lower,which deteriorates the p-type current spreading at the mesa edge.These findings show a role of thumb for the design of high efficiency micro-LEDs with wavelength below 250 nm,which will pave the way for wide applications of deep ultraviolet(DUV)micro-LEDs.展开更多
Hybrid white micro-pillar structure light emitting diodes(LEDs)have been manufacture utilizing blue micro-LEDs arrays integrated with 580 nm CIS((CuInS2-ZnS)/ZnS)core/shell quantum dots.The fabricated hybrid white mic...Hybrid white micro-pillar structure light emitting diodes(LEDs)have been manufacture utilizing blue micro-LEDs arrays integrated with 580 nm CIS((CuInS2-ZnS)/ZnS)core/shell quantum dots.The fabricated hybrid white micro-LEDs have good electrical properties,which are manifested in relatively low turn-on voltage and reverse leakage current.High-quality hybrid white light emission has been demonstrated by the hybrid white micro-LEDs after a systemic optimization,in which the corresponding color coordinates are calculated to be(0.3303,0.3501)and the calculated color temperature is 5596 K.This result indicates an effective way to achieve high-performance white LEDs and shows great promise in a large range of applications in the future including micro-displays,bioinstrumentation and visible light communication.展开更多
Conventional bioelectrical sensors and systems integrate multiple power harvesting,signal amplification and data transmission components for wireless biological signal detection.This paper reports the real-time biophy...Conventional bioelectrical sensors and systems integrate multiple power harvesting,signal amplification and data transmission components for wireless biological signal detection.This paper reports the real-time biophysical and biochemical activities can be optically captured using a microscale light-emitting diode(micro-LED),eliminating the need for complicated sensing circuit.Such a thin-film diode based device simultaneously absorbs and emits photons,enabling wireless power harvesting and signal transmission.Additionally,owing to its strong photon-recycling effects,the micro-LED^photoluminescence(PL)emission exhibits a superlinear dependence on the external conductance.Taking advantage of these unique mechanisms,instantaneous biophysical signals including galvanic skin response,pressure and temperature,and biochemical signals like ascorbic acid concentration,can be optically monitored,and it demonstrates that such an optoelectronic sensing technique outperforms a traditional tethered,electrically based sensing circuit,in terms of its footprint,accuracy and sensitivity.This presented optoelectronic sensing approach could establish promising routes to advanced biological sensors.展开更多
基金Engineering and Physical Sciences Research Council(EPSRC)(EP/M01326X/1)
文摘The low modulation bandwidth of deep-ultraviolet(UV) light sources is considered as the main reason limiting the data transmission rate of deep-UV communications. Here, we present high-bandwidth Ⅲ-nitride microlight-emitting diodes(μLEDs) emitting in the UV-C region and their applications in deep-UV communication systems. The fabricated UV-C μLEDs with 566 μm2 emission area produce an optical power of 196 μW at the 3400 A∕cm2 current density. The measured 3 dB modulation bandwidth of these μLEDs initially increases linearly with the driving current density and then saturates as 438 MHz at a current density of 71 A∕cm2, which is limited by the cutoff frequency of the commercial avalanche photodiode used for the measurement. A deep-UV communication system is further demonstrated. By using the UV-C μLED, up to 800 Mbps and 1.1 Gbps data transmission rates at bit error ratio of 3.8 × 10-3 are achieved assuming on-off keying and orthogonal frequency-division multiplexing modulation schemes, respectively.
基金This work was supported by National Key R&D Program of China(2022YFB3605103)the National Natural Science Foundation of China(62204241,U22A2084,62121005,and 61827813)+3 种基金the Natural Science Foundation of Jilin Province(20230101345JC,20230101360JC,and 20230101107JC)the Youth Innovation Promotion Association of CAS(2023223)the Young Elite Scientist Sponsorship Program By CAST(YESS20200182)the CAS Talents Program(E30122E4M0).
文摘240 nm AlGaN-based micro-LEDs with different sizes are designed and fabricated.Then,the external quantum efficiency(EQE)and light extraction efficiency(LEE)are systematically investigated by comparing size and edge effects.Here,it is revealed that the peak optical output power increases by 81.83%with the size shrinking from 50.0 to 25.0μm.Thereinto,the LEE increases by 26.21%and the LEE enhancement mainly comes from the sidewall light extraction.Most notably,transversemagnetic(TM)mode light intensifies faster as the size shrinks due to the tilted mesa side-wall and Al reflector design.However,when it turns to 12.5μm sized micro-LEDs,the output power is lower than 25.0μm sized ones.The underlying mechanism is that even though protected by SiO2 passivation,the edge effect which leads to current leakage and Shockley-Read-Hall(SRH)recombination deteriorates rapidly with the size further shrinking.Moreover,the ratio of the p-contact area to mesa area is much lower,which deteriorates the p-type current spreading at the mesa edge.These findings show a role of thumb for the design of high efficiency micro-LEDs with wavelength below 250 nm,which will pave the way for wide applications of deep ultraviolet(DUV)micro-LEDs.
基金supported by National Key R&D Program of China (2016YFB0400100)National Nature Science Foundation of China (61921005, 61674076, 61674081, 61605071, 61974062)+5 种基金Nature Science Foundation of Jiangsu Province (BY2013077, BK20141320, BE2015111)Six Talent Peaks Project of Jiangsu Province (XYDXX-081)Open Fund of the State Key Laboratory on Integrated Optoelectronics (IOSKL2017KF03)Innovation Project of Postgraduate Training in Jiangsu Province (KYCX18_0031)Fundamental Research Funds for the Central Universities (021014380096)Collaborative Innovation Center of Solid State Lighting and Energy-saving Electronics
文摘Hybrid white micro-pillar structure light emitting diodes(LEDs)have been manufacture utilizing blue micro-LEDs arrays integrated with 580 nm CIS((CuInS2-ZnS)/ZnS)core/shell quantum dots.The fabricated hybrid white micro-LEDs have good electrical properties,which are manifested in relatively low turn-on voltage and reverse leakage current.High-quality hybrid white light emission has been demonstrated by the hybrid white micro-LEDs after a systemic optimization,in which the corresponding color coordinates are calculated to be(0.3303,0.3501)and the calculated color temperature is 5596 K.This result indicates an effective way to achieve high-performance white LEDs and shows great promise in a large range of applications in the future including micro-displays,bioinstrumentation and visible light communication.
基金the National Natural Science Foundation of China(NSFC)(No.61874064)Beijing Institute of Technology Research Fund Program for Young Scholars+2 种基金Beijing Innovation Center for Future Chips,Tsinghua UniversityBeijing National Research Center for Information Science and Technology(No.BNR2019ZS01005)supported by Beijing Institute of Technology Analysis&Testing Center.
文摘Conventional bioelectrical sensors and systems integrate multiple power harvesting,signal amplification and data transmission components for wireless biological signal detection.This paper reports the real-time biophysical and biochemical activities can be optically captured using a microscale light-emitting diode(micro-LED),eliminating the need for complicated sensing circuit.Such a thin-film diode based device simultaneously absorbs and emits photons,enabling wireless power harvesting and signal transmission.Additionally,owing to its strong photon-recycling effects,the micro-LED^photoluminescence(PL)emission exhibits a superlinear dependence on the external conductance.Taking advantage of these unique mechanisms,instantaneous biophysical signals including galvanic skin response,pressure and temperature,and biochemical signals like ascorbic acid concentration,can be optically monitored,and it demonstrates that such an optoelectronic sensing technique outperforms a traditional tethered,electrically based sensing circuit,in terms of its footprint,accuracy and sensitivity.This presented optoelectronic sensing approach could establish promising routes to advanced biological sensors.
