High-performance germanium photodiodes are crucial components in silicon photonic integrated circuits for large-capacity data communication.However,the bandwidths of most germanium photodiodes are limited by the intra...High-performance germanium photodiodes are crucial components in silicon photonic integrated circuits for large-capacity data communication.However,the bandwidths of most germanium photodiodes are limited by the intractable resistance–capacitance parasitic effect.Here,we introduce a unique U-shaped electrode to alleviate this issue,reducing the parasitic effect by 36%without compromising any other performance.Experimentally,a large bandwidth of 103 GHz,an optical responsivity of 0.95 A/W at 1550 nm,and a dark current as low as 1.3 nA are achieved,leading to a record high specific detectivity.This is the first breakthrough to 100 GHz bandwidth among all vertical germanium photodiodes,to the best of our knowledge.Open eye diagrams of 120 Gb/s on-off keying and 200 Gb/s four-level pulse amplitude signals are well received.This work provides a promising solution for chip-based ultra-fast photodetection.展开更多
Flow-electrode capacitive deionization(FCDI)is an innovative technology in which an intermediate chamber plays an important role in the desalination process.However,relatively few studies have been conducted on the st...Flow-electrode capacitive deionization(FCDI)is an innovative technology in which an intermediate chamber plays an important role in the desalination process.However,relatively few studies have been conducted on the structures of these intermediate chambers.In this study,we propose a novel flow-electrode capacitive deionization device with a spindle-shaped inlet chamber(S-FCDI).The desalination rate of the S-FCDI under optimal operating conditions was 36%higher than that of the FCDI device with a conventional rectangular chamber(R-FCDI).The spindle-shaped chamber transferred 1.2μmol more ions than the rectangular chamber,based on energy per joule.Additionally,we performed a detailed analysis of different inlet chamber shapes using computational fluid dynamics software.We concluded that S-FCDI has a relatively low flow resistance and almost no stagnation zone.This provides unique insights into the development of intermediate chambers.This study may contribute to the improvement of the desalination performance in industrial applications of FCDI.展开更多
The distribution of electric field for the alignment and attachment of carbon nanotubes (CNTs) was simulated. To be attached at the desired place, the aligned and attracted CNTs should be stayed in the desired area ca...The distribution of electric field for the alignment and attachment of carbon nanotubes (CNTs) was simulated. To be attached at the desired place, the aligned and attracted CNTs should be stayed in the desired area called the stable region or the quasi-stable region for an instant where the change of electric field is minimized. Since the conical electrode has the very narrow sized quasi-stable region, few CNTs can be attached. The rectangular electrodes have a wide stable region, so lots of CNTs can be attached. The results indicate that the round electrode which has a proper sized quasi-stable region is more effective for aligning and attaching a single CNT than the conical or rectangular shaped electrodes.展开更多
The distribution effect of electric field on the alignment and attachment of carbon nanotubes （CNTs） were investigated. The experimental results were compared with the simulation results according to three different...The distribution effect of electric field on the alignment and attachment of carbon nanotubes （CNTs） were investigated. The experimental results were compared with the simulation results according to three different shaped electrodes. In previous simulation, the round shaped electrodes were expected to be more effective for aligning and attaching a single CNT between two electrodes than conical or rectangular shaped electrodes. To verify the simulation results, three different shaped electrodes were introduced and a single multi-walled carbon nanotube （MWNT） was attached. The optimal conditions for aligning and attaching MWNTs such as the frequency, applied voltage and concentration of MWNTs solution were investigated. Through repeated experiments, frequency of 100 kHz-10 MHz, applied voltage of 0.3-1.3 V^s/~m, concentration of 5 ktg/mL in MWNTs solution were obtained as a possible condition range to attach MWNTs. Under these conditions, the yield of MWNTs attachment between two electrodes was up to 70%. In previous simulation, furthermore, it was verified that the size of the stable or quasi-stable region made CNTs aligned and attached on different shaped electrodes from the comparison of the experimental and simulation results. Most single MWNT attachment was accomplished on the round shaped electrodes.展开更多
基金National Key Research and Development Program of China(2019YFB1803801)National Natural Science Foundation of China(61922034,62135004)+2 种基金Key Research and Development Program of Hubei Province(2021BAA005)Innovation Project of Optics Valley Laboratory(OVL2021BG005)Program for HUST Academic Frontier Youth Team(2018QYTD08)。
文摘High-performance germanium photodiodes are crucial components in silicon photonic integrated circuits for large-capacity data communication.However,the bandwidths of most germanium photodiodes are limited by the intractable resistance–capacitance parasitic effect.Here,we introduce a unique U-shaped electrode to alleviate this issue,reducing the parasitic effect by 36%without compromising any other performance.Experimentally,a large bandwidth of 103 GHz,an optical responsivity of 0.95 A/W at 1550 nm,and a dark current as low as 1.3 nA are achieved,leading to a record high specific detectivity.This is the first breakthrough to 100 GHz bandwidth among all vertical germanium photodiodes,to the best of our knowledge.Open eye diagrams of 120 Gb/s on-off keying and 200 Gb/s four-level pulse amplitude signals are well received.This work provides a promising solution for chip-based ultra-fast photodetection.
基金Science and Technology Project of Hebei Education Department(China)(No.QN2022038)special fund of State Key Joint Laboratory of Environment Simulation and Pollution Control(China)(No.22K05ESPCT)。
文摘Flow-electrode capacitive deionization(FCDI)is an innovative technology in which an intermediate chamber plays an important role in the desalination process.However,relatively few studies have been conducted on the structures of these intermediate chambers.In this study,we propose a novel flow-electrode capacitive deionization device with a spindle-shaped inlet chamber(S-FCDI).The desalination rate of the S-FCDI under optimal operating conditions was 36%higher than that of the FCDI device with a conventional rectangular chamber(R-FCDI).The spindle-shaped chamber transferred 1.2μmol more ions than the rectangular chamber,based on energy per joule.Additionally,we performed a detailed analysis of different inlet chamber shapes using computational fluid dynamics software.We concluded that S-FCDI has a relatively low flow resistance and almost no stagnation zone.This provides unique insights into the development of intermediate chambers.This study may contribute to the improvement of the desalination performance in industrial applications of FCDI.
基金Project supported by the Pusan National University Research GrantProject(2010-0008-276) supported by NCRC (National Core Research Center) through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology
文摘The distribution of electric field for the alignment and attachment of carbon nanotubes (CNTs) was simulated. To be attached at the desired place, the aligned and attracted CNTs should be stayed in the desired area called the stable region or the quasi-stable region for an instant where the change of electric field is minimized. Since the conical electrode has the very narrow sized quasi-stable region, few CNTs can be attached. The rectangular electrodes have a wide stable region, so lots of CNTs can be attached. The results indicate that the round electrode which has a proper sized quasi-stable region is more effective for aligning and attaching a single CNT than the conical or rectangular shaped electrodes.
基金Project supported by Pusan National University Research Grant, KoreaProject(2010-0008-276) supported by NCRC (National Core Research Center) through the National Research Foundation of Korea funded by the Ministry of Education, Science and Technology
文摘The distribution effect of electric field on the alignment and attachment of carbon nanotubes （CNTs） were investigated. The experimental results were compared with the simulation results according to three different shaped electrodes. In previous simulation, the round shaped electrodes were expected to be more effective for aligning and attaching a single CNT between two electrodes than conical or rectangular shaped electrodes. To verify the simulation results, three different shaped electrodes were introduced and a single multi-walled carbon nanotube （MWNT） was attached. The optimal conditions for aligning and attaching MWNTs such as the frequency, applied voltage and concentration of MWNTs solution were investigated. Through repeated experiments, frequency of 100 kHz-10 MHz, applied voltage of 0.3-1.3 V^s/~m, concentration of 5 ktg/mL in MWNTs solution were obtained as a possible condition range to attach MWNTs. Under these conditions, the yield of MWNTs attachment between two electrodes was up to 70%. In previous simulation, furthermore, it was verified that the size of the stable or quasi-stable region made CNTs aligned and attached on different shaped electrodes from the comparison of the experimental and simulation results. Most single MWNT attachment was accomplished on the round shaped electrodes.
