We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the thre...We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.展开更多
We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured u...We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured uniformly by the 200-mm-wafer platform.The performance of the devices is systematically studied,including their magnetic properties,switch-ing behaviors,endurance and data retention.The successful integration of SOT devices within the 200-mm-wafer manufactur-ing platform provides a feasible way to industrialize SOT MRAMs.It is expected to obtain excellent performance of the devices by further optimizing the MTJ film stacks and the corresponding fabrication processes in the future.展开更多
Vanadium-based cathodes have received widespread attention in the field of aqueous zinc-ion batteries,presenting a promising prospect for stationary energy storage applications.However,the rapid capacity decay at low ...Vanadium-based cathodes have received widespread attention in the field of aqueous zinc-ion batteries,presenting a promising prospect for stationary energy storage applications.However,the rapid capacity decay at low current densities has hampered their development.In particular,capacity stability at low current densities is a requisite in numerous practical applications,typically encompassing peak load regulation of the electricity grid,household energy storage systems,and uninterrupted power supplies.Despite possessing notably high specific capacities,vanadium-based materials exhibit severe instability at low current densities.Moreover,the issue of stabilizing electrode reactions at these densities for vanadium-based materials has been explored insufficiently in existing research.This review aims to investigate the matter of stability in vanadium-based materials at low current densities by concentrating on the mechanisms of capacity fading and optimization strategies.It proposes a comprehensive approach that includes electrolyte optimization,electrode modulation,and electrochemical operational conditions.Finally,we presented several crucial prospects for advancing the practical development of vanadium-based aqueous zinc-ion batteries.展开更多
基金Supported by the National Basic Research Program of China under Grant Nos 2013CB632801 and 2013CB632803the National Natural Science Foundation of China under Grant Nos 61435014,61306058 and 61274094the Beijing Natural Science Foundation under Grant No 4144086
文摘We report on the room-temperature cascade laser （QCL） at λ -4.7μm. cw operation of a surface grating Both grating design and material distributed feedback （DFB） quantum optimization are used to decrease the threshold current density and to increase the output power. For a high-reflectivity-coated 13-μm-wide and 4- mm-long laser, high wall-plug efficiency of 6% is obtained at 20℃ from a single facet producing over I W of ew output power. The threshold current density of DFB QCL is as low as 1.13kA/cm^2 at 10℃ and 1.34kA/cm2 at 30℃ in cw mode. Stable single-mode emission with a side-mode suppression ratio of about 30 dB is observed in tile working temperature range of 20-50℃.
基金supported by the National Key Research and Development Program of China(Grant Nos.2021YFB3601303,2021YFB3601304,2021YFB3601300)National Natural Science Foundation of China(Nos.62001014 and 62171013)。
文摘We demonstrate in-plane field-free-switching spin-orbit torque(SOT)magnetic tunnel junction(MTJ)devices that are capable of low switching current density,fast speed,high reliability,and,most importantly,manufactured uniformly by the 200-mm-wafer platform.The performance of the devices is systematically studied,including their magnetic properties,switch-ing behaviors,endurance and data retention.The successful integration of SOT devices within the 200-mm-wafer manufactur-ing platform provides a feasible way to industrialize SOT MRAMs.It is expected to obtain excellent performance of the devices by further optimizing the MTJ film stacks and the corresponding fabrication processes in the future.
基金supported by the National Natural Science Foundation of China(52072411)the Scientific Research Program of the Higher Education Institution of Xinjiang(XJEDU2022P001)+1 种基金the Central South University Innovation-Driven Research Programme(2023CXQD038)the National Key Research and Development Program of China(2023YFC2908305)。
文摘Vanadium-based cathodes have received widespread attention in the field of aqueous zinc-ion batteries,presenting a promising prospect for stationary energy storage applications.However,the rapid capacity decay at low current densities has hampered their development.In particular,capacity stability at low current densities is a requisite in numerous practical applications,typically encompassing peak load regulation of the electricity grid,household energy storage systems,and uninterrupted power supplies.Despite possessing notably high specific capacities,vanadium-based materials exhibit severe instability at low current densities.Moreover,the issue of stabilizing electrode reactions at these densities for vanadium-based materials has been explored insufficiently in existing research.This review aims to investigate the matter of stability in vanadium-based materials at low current densities by concentrating on the mechanisms of capacity fading and optimization strategies.It proposes a comprehensive approach that includes electrolyte optimization,electrode modulation,and electrochemical operational conditions.Finally,we presented several crucial prospects for advancing the practical development of vanadium-based aqueous zinc-ion batteries.
