A new internal waverider inlet with a rectangular shape of entrance and exit in front view is designed at Ma=6.0.The design is based on a better basic flowfield ICFC than traditional one and derived with the technolog...A new internal waverider inlet with a rectangular shape of entrance and exit in front view is designed at Ma=6.0.The design is based on a better basic flowfield ICFC than traditional one and derived with the technology of stream tracing and shock cutting.Comparison between the newly designed inlet and a typical sidewall compression inlet is given.The design Mach number and entrance shape of this new inlet are chosen according to the sidewall compression inlet.Numerical results show that most of the performance parameters of the internal waverider inlet are a bit higher than the sidewall inlet,such as the flow capture coefficient,total pressure recovery and the kinetic efficiency.The performances of these two inlets at off-design points are compared.The internal waverider inlet can capture more than 91% of incoming flow under all simulated conditions.Results show that internal waverider inlet using 3-D compression and high flow capture coefficient is a kind of fixed-geometry inlet with better performance.展开更多
Although the 5G wireless network has made significant advances,it is not enough to accommodate the rapidly rising requirement for broader bandwidth in post-5G and 6G eras.As a result,emerging technologies in higher fr...Although the 5G wireless network has made significant advances,it is not enough to accommodate the rapidly rising requirement for broader bandwidth in post-5G and 6G eras.As a result,emerging technologies in higher frequencies including visible light communication(VLC),are becoming a hot topic.In particular,LED-based VLC is foreseen as a key enabler for achieving data rates at the Tb/s level in indoor scenarios using multi-color LED arrays with wavelength division multiplexing(WDM)technology.This paper proposes an optimized multi-color LED array chip for high-speed VLC systems.Its long-wavelength GaN-based LED units are remarkably enhanced by V-pit structure in their efficiency,especially in the“yellow gap”region,and it achieves significant improvement in data rate compared with earlier research.This work investigates the V-pit structure and tries to provide insight by introducing a new equivalent circuit model,which provides an explanation of the simulation and experiment results.In the final test using a laboratory communication system,the data rates of eight channels from short to long wavelength are 3.91 Gb/s,3.77 Gb/s,3.67 Gb/s,4.40 Gb/s,3.78 Gb/s,3.18 Gb/s,4.31 Gb/s,and 4.35 Gb/s(31.38 Gb/s in total),with advanced digital signal processing(DSP)techniques including digital equalization technique and bit-power loading discrete multitone(DMT)modulation format.展开更多
With regard to micro-light-emitting diodes(micro-LEDs),their excellent brightness,low energy consumption,and ultrahigh resolution are significant advantages.However,the large size of traditional inorganic phosphors an...With regard to micro-light-emitting diodes(micro-LEDs),their excellent brightness,low energy consumption,and ultrahigh resolution are significant advantages.However,the large size of traditional inorganic phosphors and the number of side defects have restricted the practical applications of small sized micro-LEDs.Recently,quantum dot(QD)and nonradiative energy transfer(NRET)have been proposed to solve existing problems.QDs possess nanoscale dimensions and high luminous efficiency,and they are suitable for NRET because they are able to nearly contact the micro-LED chip.The NRET between QDs and micro-LED chip further improves the color conversion efficiency(CCE)and effective quantum yield(EQY)of full-color micro-LED devices.In this review,we discuss the NRET mechanism for QD micro-LED devices,and then nano-pillar LED,nano-hole LED,and nano-ring LED are introduced in detail.These structures are beneficial to the NRET between QD and micro-LED,especially nano-ring LED.Finally,the challenges and future envisions have also been described.展开更多
we investigate the effects of 60^Co γ-ray irradiation on the 130 nm partially-depleted silicon-on-isolator （PDSOI） input/output （I/O） n-MOSFETs. A shallow trench isolation （STI） parasitic transistor is responsi...we investigate the effects of 60^Co γ-ray irradiation on the 130 nm partially-depleted silicon-on-isolator （PDSOI） input/output （I/O） n-MOSFETs. A shallow trench isolation （STI） parasitic transistor is responsible for the observed hump in the back-gate transfer characteristic curve. The STI parasitic transistor, in which the trench oxide acts as the gate oxide, is sensitive to the radiation, and it introduces a new way to characterize the total ionizing dose （TID） responses in the STI oxide. A radiation enhanced drain induced barrier lower （DIBL） effect is observed in the STI parasitic transistor. It is manifested as the drain bias dependence of the radiation-induced off-state leakage and the increase of the DIBL parameter in the STI parasitic transistor after irradiation. Increasing the doping concentration in the whole body region or just near the STI sidewall can increase the threshold voltage of the STI parasitic transistor, and further reduce the radiation-induced off-state leakage. Moreover, we find that the radiation-induced trapped charge in the buried oxide leads to an obvious front-gate threshold voltage shift through the coupling effect. The high doping concentration in the body can effectively suppress the radiation-induced coupling effect.展开更多
We optimize the room-temperature etching of InP using Cl2/CH4/H2 and Cl2/N2 inductively coupled plasma reactive ions. A design of experiment is used in the optimization. The results, in terms of etch rate, surface rou...We optimize the room-temperature etching of InP using Cl2/CH4/H2 and Cl2/N2 inductively coupled plasma reactive ions. A design of experiment is used in the optimization. The results, in terms of etch rate, surface roughness and etched profile, are presented. These Cl2-based recipes do not require substrate heating and thus can be more cost effectively and widely applied. The Cl2/CH4/H2 process is able to give a higher etch rate （about 850 nm/min） and cleaner surface with less polymer formation compared to the conventional CH4/H2 process. The Cl2/N2 process produces even higher etch rate （as high as 2μm/rain）, but rougher surface with slight sidewall undercut. The Cl2/N2 process also has no polymer formation due to the absence of methane gas. Both the processes give very good selectivity to the silicon dioxide （SiO2） etch mask. The selectivity of InP to the oxide mask （up to 55：1） for the Cl2/N2 process is one of the highest reported so far. The etched structures possess reasonably good sidewall verticality and surface quality comparable to that obtained under elevated temperature condition （〉 200℃）.展开更多
文摘A new internal waverider inlet with a rectangular shape of entrance and exit in front view is designed at Ma=6.0.The design is based on a better basic flowfield ICFC than traditional one and derived with the technology of stream tracing and shock cutting.Comparison between the newly designed inlet and a typical sidewall compression inlet is given.The design Mach number and entrance shape of this new inlet are chosen according to the sidewall compression inlet.Numerical results show that most of the performance parameters of the internal waverider inlet are a bit higher than the sidewall inlet,such as the flow capture coefficient,total pressure recovery and the kinetic efficiency.The performances of these two inlets at off-design points are compared.The internal waverider inlet can capture more than 91% of incoming flow under all simulated conditions.Results show that internal waverider inlet using 3-D compression and high flow capture coefficient is a kind of fixed-geometry inlet with better performance.
基金This research was funded by the National Key Research and Development Program of China(2022YFB2802803)the Natural Science Foundation of China Project(No.61925104,No.62031011,No.62201157,No.62074072).
文摘Although the 5G wireless network has made significant advances,it is not enough to accommodate the rapidly rising requirement for broader bandwidth in post-5G and 6G eras.As a result,emerging technologies in higher frequencies including visible light communication(VLC),are becoming a hot topic.In particular,LED-based VLC is foreseen as a key enabler for achieving data rates at the Tb/s level in indoor scenarios using multi-color LED arrays with wavelength division multiplexing(WDM)technology.This paper proposes an optimized multi-color LED array chip for high-speed VLC systems.Its long-wavelength GaN-based LED units are remarkably enhanced by V-pit structure in their efficiency,especially in the“yellow gap”region,and it achieves significant improvement in data rate compared with earlier research.This work investigates the V-pit structure and tries to provide insight by introducing a new equivalent circuit model,which provides an explanation of the simulation and experiment results.In the final test using a laboratory communication system,the data rates of eight channels from short to long wavelength are 3.91 Gb/s,3.77 Gb/s,3.67 Gb/s,4.40 Gb/s,3.78 Gb/s,3.18 Gb/s,4.31 Gb/s,and 4.35 Gb/s(31.38 Gb/s in total),with advanced digital signal processing(DSP)techniques including digital equalization technique and bit-power loading discrete multitone(DMT)modulation format.
基金supports from the National Natural Science Foundation of China(11904302,61921005)Major Project of the Science and Technology in Fujian Province of China(2019HZ020013)Major Science and Technology Projects in Xiamen of China(3502Z20191015).
文摘With regard to micro-light-emitting diodes(micro-LEDs),their excellent brightness,low energy consumption,and ultrahigh resolution are significant advantages.However,the large size of traditional inorganic phosphors and the number of side defects have restricted the practical applications of small sized micro-LEDs.Recently,quantum dot(QD)and nonradiative energy transfer(NRET)have been proposed to solve existing problems.QDs possess nanoscale dimensions and high luminous efficiency,and they are suitable for NRET because they are able to nearly contact the micro-LED chip.The NRET between QDs and micro-LED chip further improves the color conversion efficiency(CCE)and effective quantum yield(EQY)of full-color micro-LED devices.In this review,we discuss the NRET mechanism for QD micro-LED devices,and then nano-pillar LED,nano-hole LED,and nano-ring LED are introduced in detail.These structures are beneficial to the NRET between QD and micro-LED,especially nano-ring LED.Finally,the challenges and future envisions have also been described.
基金supported by the Opening Project of Science and Technology on Reliability Physics and Application Technology of Electronic Component Laboratory,China(Grant No.ZHD201205)the National Natural Science Foundation of China(Grant No.61106103)
文摘we investigate the effects of 60^Co γ-ray irradiation on the 130 nm partially-depleted silicon-on-isolator （PDSOI） input/output （I/O） n-MOSFETs. A shallow trench isolation （STI） parasitic transistor is responsible for the observed hump in the back-gate transfer characteristic curve. The STI parasitic transistor, in which the trench oxide acts as the gate oxide, is sensitive to the radiation, and it introduces a new way to characterize the total ionizing dose （TID） responses in the STI oxide. A radiation enhanced drain induced barrier lower （DIBL） effect is observed in the STI parasitic transistor. It is manifested as the drain bias dependence of the radiation-induced off-state leakage and the increase of the DIBL parameter in the STI parasitic transistor after irradiation. Increasing the doping concentration in the whole body region or just near the STI sidewall can increase the threshold voltage of the STI parasitic transistor, and further reduce the radiation-induced off-state leakage. Moreover, we find that the radiation-induced trapped charge in the buried oxide leads to an obvious front-gate threshold voltage shift through the coupling effect. The high doping concentration in the body can effectively suppress the radiation-induced coupling effect.
文摘We optimize the room-temperature etching of InP using Cl2/CH4/H2 and Cl2/N2 inductively coupled plasma reactive ions. A design of experiment is used in the optimization. The results, in terms of etch rate, surface roughness and etched profile, are presented. These Cl2-based recipes do not require substrate heating and thus can be more cost effectively and widely applied. The Cl2/CH4/H2 process is able to give a higher etch rate （about 850 nm/min） and cleaner surface with less polymer formation compared to the conventional CH4/H2 process. The Cl2/N2 process produces even higher etch rate （as high as 2μm/rain）, but rougher surface with slight sidewall undercut. The Cl2/N2 process also has no polymer formation due to the absence of methane gas. Both the processes give very good selectivity to the silicon dioxide （SiO2） etch mask. The selectivity of InP to the oxide mask （up to 55：1） for the Cl2/N2 process is one of the highest reported so far. The etched structures possess reasonably good sidewall verticality and surface quality comparable to that obtained under elevated temperature condition （〉 200℃）.
