Designing and manufacturing cost-effective absorbers that can cover the full-spectrum of solar irradiation is still critically important for solar harvesting.Utilizing control of the lightwave reflection and transmiss...Designing and manufacturing cost-effective absorbers that can cover the full-spectrum of solar irradiation is still critically important for solar harvesting.Utilizing control of the lightwave reflection and transmission,metamaterials realize high absorption over a relatively wide bandwidth.Here,a truncated circular cone metasurface(TCCM)composed of alternating multiple layers of titanium(Ti)and silicon dioxide(SiO_(2))is presented.Enabled by the synergetic of surface plasmon resonances and Fabry-Pérot resonances,the TCCM simultaneously achieves high absorptivity(exceed 90%),and absorption broadband covers almost the entire solar irradiation spectrum.In addition,the novel absorber exhibits great photo-thermal property.By exploiting the ultrahigh melting point of Ti and SiO_(2),high-efficiency solar irradiation absorption and heat release have been achieved at 700℃when the solar concentration ratio is 500(i.e.,incident light intensity at 5×10^(5) W/m^(2)).It is worth noting that the photo-thermal efficiency is almost unchanged when the incident angle increases from 0°to 45°.The outstanding capacity for solar harvesting and light-to-heat reported in this paper suggests that TCCM has great potential in photothermal therapies,solar desalination,and radiative cooling,etc.展开更多
III-nitride materials are of great importance in the development of modern optoelectronics,but they have been limited over years by low light utilization rate and high dislocation densities in heteroepitaxial films gr...III-nitride materials are of great importance in the development of modern optoelectronics,but they have been limited over years by low light utilization rate and high dislocation densities in heteroepitaxial films grown on foreign substrate with limited refractive index contrast and large lattice mismatches.Here,we demonstrate a paradigm of high-throughput manufacturing bioinspired microstructures on warped substrates by flexible nanoimprint lithography for promoting the light extraction capability.We design a flexible nanoimprinting mold of copolymer and a two-step etching process that enable high-efficiency fabrication of nanoimprinted compound-eye-like Al2O3 microstructure(NCAM)and nanoimprinted compound-eye-like SiO_(2)microstructure(NCSM)template,achieving a 6.4-fold increase in throughput and 25%savings in economic costs over stepper projection lithography.Compared to NCAM template,we find that the NCSM template can not only improve the light extraction capability,but also modulate the morphology of AlN nucleation layer and reduce the formation of misoriented GaN grains on the inclined sidewall of microstructures,which suppresses the dislocations generated during coalescence,resulting in 40%reduction in dislocation density.This study provides a low-cost,high-quality,and high-throughput solution for manufacturing microstructures on warped surfaces of III-nitride optoelectronic devices.展开更多
AlGaN-based light-emitting diodes(LEDs)operating in the deep-ultraviolet(DUV)spectral range(210–280 nm)have demonstrated potential applications in physical sterilization.However,the poor external quantum efficiency(E...AlGaN-based light-emitting diodes(LEDs)operating in the deep-ultraviolet(DUV)spectral range(210–280 nm)have demonstrated potential applications in physical sterilization.However,the poor external quantum efficiency(EQE)hinders further advances in the emission performance of AlGaN-based DUV LEDs.Here,we demonstrate the performance of 270-nm AlGaN-based DUV LEDs beyond the state-of-the-art by exploiting the innovative combination of bandgap engineering and device craft.By adopting tailored multiple quantum wells(MQWs),a reflective Al reflector,a low-optical-loss tunneling junction(TJ)and a dielectric SiO_(2)insertion structure(IS-SiO_(2)),outstanding light output powers(LOPs)of 140.1 mW are achieved in our DUV LEDs at 850 mA.The EQEs of our DUV LEDs are 4.5 times greater than those of their conventional counterparts.This comprehensive approach overcomes the major difficulties commonly faced in the pursuit of high-performance AlGaN-based DUV LEDs,such as strong quantum-confined Stark effect(QCSE),severe optical absorption in the p-electrode/ohmic contact layer and poor transverse magnetic(TM)-polarized light extraction.Furthermore,the on-wafer electroluminescence characterization validated the scalability of our DUV LEDs to larger production scales.Our work is promising for the development of highly efficient AlGaN-based DUV LEDs.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11804134 and 11464019)the Natural Science Foundation of Jiangxi Province,China(Grant No.20202BBEL53036).
文摘Designing and manufacturing cost-effective absorbers that can cover the full-spectrum of solar irradiation is still critically important for solar harvesting.Utilizing control of the lightwave reflection and transmission,metamaterials realize high absorption over a relatively wide bandwidth.Here,a truncated circular cone metasurface(TCCM)composed of alternating multiple layers of titanium(Ti)and silicon dioxide(SiO_(2))is presented.Enabled by the synergetic of surface plasmon resonances and Fabry-Pérot resonances,the TCCM simultaneously achieves high absorptivity(exceed 90%),and absorption broadband covers almost the entire solar irradiation spectrum.In addition,the novel absorber exhibits great photo-thermal property.By exploiting the ultrahigh melting point of Ti and SiO_(2),high-efficiency solar irradiation absorption and heat release have been achieved at 700℃when the solar concentration ratio is 500(i.e.,incident light intensity at 5×10^(5) W/m^(2)).It is worth noting that the photo-thermal efficiency is almost unchanged when the incident angle increases from 0°to 45°.The outstanding capacity for solar harvesting and light-to-heat reported in this paper suggests that TCCM has great potential in photothermal therapies,solar desalination,and radiative cooling,etc.
基金supported by the National Natural Science Foundation of China(52075394)the National Key R&D Program of China(2022YFB3603603 and 2021YFB3600204)+1 种基金the Key Research and Development Program of Hubei Province(2023BAB137)the Knowledge Innovation Program of Wuhan-Basic Research,the National Youth Talent Support Program,and the Fundamental Research Funds for the Central Universities.
文摘III-nitride materials are of great importance in the development of modern optoelectronics,but they have been limited over years by low light utilization rate and high dislocation densities in heteroepitaxial films grown on foreign substrate with limited refractive index contrast and large lattice mismatches.Here,we demonstrate a paradigm of high-throughput manufacturing bioinspired microstructures on warped substrates by flexible nanoimprint lithography for promoting the light extraction capability.We design a flexible nanoimprinting mold of copolymer and a two-step etching process that enable high-efficiency fabrication of nanoimprinted compound-eye-like Al2O3 microstructure(NCAM)and nanoimprinted compound-eye-like SiO_(2)microstructure(NCSM)template,achieving a 6.4-fold increase in throughput and 25%savings in economic costs over stepper projection lithography.Compared to NCAM template,we find that the NCSM template can not only improve the light extraction capability,but also modulate the morphology of AlN nucleation layer and reduce the formation of misoriented GaN grains on the inclined sidewall of microstructures,which suppresses the dislocations generated during coalescence,resulting in 40%reduction in dislocation density.This study provides a low-cost,high-quality,and high-throughput solution for manufacturing microstructures on warped surfaces of III-nitride optoelectronic devices.
基金financial support from the National Natural Science Foundation of China(Nos.52075394 and 51675386)the National Key Research and Development Program of China(Nos.2021YFB3600200 and 2022YFB3603603)+1 种基金the Key Research and Development Program of Hubei Province(No.2023BAB137)the Knowledge Innovation Program of Wuhan-Basic Research,the Fundamental Research Funds for the Central Universities,and the National Youth Talent Support Program.
文摘AlGaN-based light-emitting diodes(LEDs)operating in the deep-ultraviolet(DUV)spectral range(210–280 nm)have demonstrated potential applications in physical sterilization.However,the poor external quantum efficiency(EQE)hinders further advances in the emission performance of AlGaN-based DUV LEDs.Here,we demonstrate the performance of 270-nm AlGaN-based DUV LEDs beyond the state-of-the-art by exploiting the innovative combination of bandgap engineering and device craft.By adopting tailored multiple quantum wells(MQWs),a reflective Al reflector,a low-optical-loss tunneling junction(TJ)and a dielectric SiO_(2)insertion structure(IS-SiO_(2)),outstanding light output powers(LOPs)of 140.1 mW are achieved in our DUV LEDs at 850 mA.The EQEs of our DUV LEDs are 4.5 times greater than those of their conventional counterparts.This comprehensive approach overcomes the major difficulties commonly faced in the pursuit of high-performance AlGaN-based DUV LEDs,such as strong quantum-confined Stark effect(QCSE),severe optical absorption in the p-electrode/ohmic contact layer and poor transverse magnetic(TM)-polarized light extraction.Furthermore,the on-wafer electroluminescence characterization validated the scalability of our DUV LEDs to larger production scales.Our work is promising for the development of highly efficient AlGaN-based DUV LEDs.
