We report a theoretical study of a broadband Si/graded-SiGe/Ge/Ge0.9Sn0.1 p–i–n photodetector with a flat response based on modulating thickness of the layers in the active region.The responsivity of the photodetect...We report a theoretical study of a broadband Si/graded-SiGe/Ge/Ge0.9Sn0.1 p–i–n photodetector with a flat response based on modulating thickness of the layers in the active region.The responsivity of the photodetector is about 0.57 A/W in the range of 700 to 1800 nm.This structure is suitable for silicon-based epitaxial growth.Annealing is technically applied to form the graded-SiGe.The photodetector reaches a cut-off wavelength at^2300 nm and a low dark-current density under 3 V reverse bias about 0.17 mA/cm^2 is achieved theoretical at room temperature.This work is of great significance for silicon-based detection and communication,from visible to infrared.展开更多
In this study, we propose a generalized pseudoclassical theory for the kicked rotor model in an attempt to discern the footprints of the classical dynamics in the deep quantum regime. Compared with the previous pseudo...In this study, we propose a generalized pseudoclassical theory for the kicked rotor model in an attempt to discern the footprints of the classical dynamics in the deep quantum regime. Compared with the previous pseudoclassical theory that applies only in the neighborhoods of the lowest two quantum resonances, the proposed theory is applicable in the neighborhoods of all quantum resonances in principle by considering the quantum effect of the free rotation at a quantum resonance. In particular, it is confirmed by simulations that the quantum wavepacket dynamics can be successfully forecasted based on the generalized pseudoclassical dynamics, offering an intriguing example where it is feasible to bridge the dynamics in the deep quantum regime to the classical dynamics. The application of the generalized pseudoclassical theory to the PT-symmetric kicked rotor is also discussed.展开更多
An interlayer is usually employed to tackle the interfacial instability issue between solid electrolytes(SEs)and Li metal caused by the side reaction.However,the failure mechanism of the ionic conductor interlayers,es...An interlayer is usually employed to tackle the interfacial instability issue between solid electrolytes(SEs)and Li metal caused by the side reaction.However,the failure mechanism of the ionic conductor interlayers,especially the influence from electron penetration,remains largely unknown.Herein,using Li1.3Al0.3Ti1.7(PO4)3(LATP)as the model SE and LiF as the interlayer,we use metal semiconductor contact barrier theory to reveal the failure origin of Li/LiF@LATP interface based on the calculation results of density functional theory(DFT),in which electrons can easily tunnel through the LiF grain boundary with F vacancies due to its narrow barrier width against electron injection,followed by the reduction of LATP.Remarkably,an Al-LiF bilayer between Li/LATP is found to dramatically promote the interfacial stability,due to the highly increased barrier width and homogenized electric field at the interface.Consequently,the Li symmetric cells with Al-LiF bilayer can exhibit excellent cyclability of more than 2,000 h superior to that interlayered by LiF monolayer(~860 h).Moreover,the Li/Al-LiF@LATP/LiFePO4 solid-state batteries deliver a capacity retention of 83.2%after 350 cycles at 0.5 C.Our findings emphasize the importance of tuning the electron transport behavior by optimizing the potential barrier for the interface design in high-performance solid-state batteries.展开更多
基金This work was supported by National Basic Research Program of China(No.2013CB632103)National Natural Science Foundation of China(Nos.61534005 and 61474081)Scientific Research Project of Fujian Provincial Department of Education(No.JA15651).
文摘We report a theoretical study of a broadband Si/graded-SiGe/Ge/Ge0.9Sn0.1 p–i–n photodetector with a flat response based on modulating thickness of the layers in the active region.The responsivity of the photodetector is about 0.57 A/W in the range of 700 to 1800 nm.This structure is suitable for silicon-based epitaxial growth.Annealing is technically applied to form the graded-SiGe.The photodetector reaches a cut-off wavelength at^2300 nm and a low dark-current density under 3 V reverse bias about 0.17 mA/cm^2 is achieved theoretical at room temperature.This work is of great significance for silicon-based detection and communication,from visible to infrared.
基金supported by the National Natural Science Foundation of China (Grant Nos. 12075198, 12247106, and 12247101)。
文摘In this study, we propose a generalized pseudoclassical theory for the kicked rotor model in an attempt to discern the footprints of the classical dynamics in the deep quantum regime. Compared with the previous pseudoclassical theory that applies only in the neighborhoods of the lowest two quantum resonances, the proposed theory is applicable in the neighborhoods of all quantum resonances in principle by considering the quantum effect of the free rotation at a quantum resonance. In particular, it is confirmed by simulations that the quantum wavepacket dynamics can be successfully forecasted based on the generalized pseudoclassical dynamics, offering an intriguing example where it is feasible to bridge the dynamics in the deep quantum regime to the classical dynamics. The application of the generalized pseudoclassical theory to the PT-symmetric kicked rotor is also discussed.
基金This research was supported by the National Natural Science Foundation of China(Nos.52072323,52172240,and 11874307)Natural Science Foundation of Jiangxi Province(No.20192ACBL20048)+3 种基金Natural Science Foundation of Jiangsu Province(No.BK20200800)Scientific Research Project of Fujian Provincial Department of Education(No.JAT191150)the Fundamental Research Funds for the Central Universities(No.20720200075)the Double-First Class Foundation of Materials and Intelligent Manufacturing Discipline of Xiamen University.
文摘An interlayer is usually employed to tackle the interfacial instability issue between solid electrolytes(SEs)and Li metal caused by the side reaction.However,the failure mechanism of the ionic conductor interlayers,especially the influence from electron penetration,remains largely unknown.Herein,using Li1.3Al0.3Ti1.7(PO4)3(LATP)as the model SE and LiF as the interlayer,we use metal semiconductor contact barrier theory to reveal the failure origin of Li/LiF@LATP interface based on the calculation results of density functional theory(DFT),in which electrons can easily tunnel through the LiF grain boundary with F vacancies due to its narrow barrier width against electron injection,followed by the reduction of LATP.Remarkably,an Al-LiF bilayer between Li/LATP is found to dramatically promote the interfacial stability,due to the highly increased barrier width and homogenized electric field at the interface.Consequently,the Li symmetric cells with Al-LiF bilayer can exhibit excellent cyclability of more than 2,000 h superior to that interlayered by LiF monolayer(~860 h).Moreover,the Li/Al-LiF@LATP/LiFePO4 solid-state batteries deliver a capacity retention of 83.2%after 350 cycles at 0.5 C.Our findings emphasize the importance of tuning the electron transport behavior by optimizing the potential barrier for the interface design in high-performance solid-state batteries.