Silicon Hall-effect sensors have been widely used in industry and research fields due to their straightforward fabrication process and CMOS compatibility.However,as their material property limitations,technicians usua...Silicon Hall-effect sensors have been widely used in industry and research fields due to their straightforward fabrication process and CMOS compatibility.However,as their material property limitations,technicians usually implement complex CMOS circuits to improve the sensors’performance including temperature drift and offset compensation for fitting tough situation,but it is no doubt that it increases the design complexity and the sensor area.Gallium arsenide(GaAs)is a superior material of Hall-effect device because of its large mobility and stable temperature characteristics.Concerning there is no specified modelling of GaAs Hall-effect device,this paper investigated its modelling by using finite element method(FEM)software Silvaco TCAD®to help and guide GaAs Hall-effect device fabrication.The modeled sensor has been fabricated and its experimental results are in agreement with the simulation results.Comparing to our previous silicon Hall-effect sensor,the GaAs Hall-effect sensor demonstrates potential and reliable benchmark for the future Hall magnetic sensor developments.展开更多
A novel system configuration of fiber optic sensor based on optical abso rption is proposed. Several compensation measures are discussed. A simulated exp eriment is designed and the output curve of system is given. Th...A novel system configuration of fiber optic sensor based on optical abso rption is proposed. Several compensation measures are discussed. A simulated exp eriment is designed and the output curve of system is given. The experiment al result shows that these compensation measures are effective on dynamic distu rbances which are caused by background light and optical fiber bend. In addition , the drifts in the light source intensity, fiber losses, and photodetector effi ciency are also compensated.展开更多
Experiments with the limited space-charge accumulation（LSA） mode of oscillation in a large gap semiinsulating （SI） GaAs photoconductive semiconductor switch（PCSS） are discussed.It has been observed that growth a...Experiments with the limited space-charge accumulation（LSA） mode of oscillation in a large gap semiinsulating （SI） GaAs photoconductive semiconductor switch（PCSS） are discussed.It has been observed that growth and drift of a photo-activated charge domain（PACD） are quenched only when the bias voltage is more than twice the threshold voltage.The original negative resistance characteristics are directly utilized in the LSA mode;during LSA operation the spatial average of the electric field varies over a large portion of the negative differential mobility region of the velocity-electric field characteristic.The work efficiency of an SI GaAs PCSS is remarkably enhanced by electric field excursions into the positive resistance region when the total electric field is only below the threshold part of the time.The LSA mode can only operate in the certain conditions that satisfy the quenching of the accumulation layer and the smaller initial domain voltage.展开更多
The quantum harmonic oscillator(QHO),one of the most important and ubiquitous model systems in quantum mechanics,features equally spaced energy levels or eigenstates.Here we present a new class of nearly ideal QHOs fo...The quantum harmonic oscillator(QHO),one of the most important and ubiquitous model systems in quantum mechanics,features equally spaced energy levels or eigenstates.Here we present a new class of nearly ideal QHOs formed by hydrogenic substitutional dopants in an AlGaAs/GaAs heterostructure.On the basis of model calculations,we demonstrate that,when aδ-doping Si donor substitutes the Ga/Al lattice site close to AlGaAs/GaAs heterointerface,a hydrogenic Si QHO,characterized by a restoring Coulomb force producing square law harmonic potential,is formed.This gives rise to QHO states with energy spacing of~8–9 meV.We experimentally confirm this proposal by utilizing gate tuning and measuring QHO states using an aluminum single-electron transistor(SET).A sharp and fast oscillation with period of~7–8 mV appears in addition to the regular Coulomb blockade(CB)oscillation with much larger period,for positive gate biases above 0.5 V.The observation of fast oscillation and its behavior is quantitatively consistent with our theoretical result,manifesting the harmonic motion of electrons from the QHO.Our results might establish a general principle to design,construct and manipulate QHOs in semiconductor heterostructures,opening future possibilities for their quantum applications.展开更多
基金the National Natural Science Foundation of China(NSFC)under Grant 61771111Sichuan Provincial Science and Technology Important Projects under Grant 22ZDYF2805+1 种基金supported by the Open Foundation of the State Key Laboratory of Electronic Thin Films and Integrated Devices under Grant KFJJ202006,and supported by Intelligent Terminal Key Laboratory of Sichuan Province under Grant SCITLAB-1001the National Natural Science Foundation of China under Grant 62090012.
文摘Silicon Hall-effect sensors have been widely used in industry and research fields due to their straightforward fabrication process and CMOS compatibility.However,as their material property limitations,technicians usually implement complex CMOS circuits to improve the sensors’performance including temperature drift and offset compensation for fitting tough situation,but it is no doubt that it increases the design complexity and the sensor area.Gallium arsenide(GaAs)is a superior material of Hall-effect device because of its large mobility and stable temperature characteristics.Concerning there is no specified modelling of GaAs Hall-effect device,this paper investigated its modelling by using finite element method(FEM)software Silvaco TCAD®to help and guide GaAs Hall-effect device fabrication.The modeled sensor has been fabricated and its experimental results are in agreement with the simulation results.Comparing to our previous silicon Hall-effect sensor,the GaAs Hall-effect sensor demonstrates potential and reliable benchmark for the future Hall magnetic sensor developments.
文摘A novel system configuration of fiber optic sensor based on optical abso rption is proposed. Several compensation measures are discussed. A simulated exp eriment is designed and the output curve of system is given. The experiment al result shows that these compensation measures are effective on dynamic distu rbances which are caused by background light and optical fiber bend. In addition , the drifts in the light source intensity, fiber losses, and photodetector effi ciency are also compensated.
基金Project supported by the National Natural Science Foundation of China(Nos.50837005,11204264)the Research Fund for Doctors of Xinjiang Normal University(No.XJNUBS 1220)the Research Fund for the Outstanding Young Teacher of Xinjiang Normal University (No.XJNU1214)
文摘Experiments with the limited space-charge accumulation（LSA） mode of oscillation in a large gap semiinsulating （SI） GaAs photoconductive semiconductor switch（PCSS） are discussed.It has been observed that growth and drift of a photo-activated charge domain（PACD） are quenched only when the bias voltage is more than twice the threshold voltage.The original negative resistance characteristics are directly utilized in the LSA mode;during LSA operation the spatial average of the electric field varies over a large portion of the negative differential mobility region of the velocity-electric field characteristic.The work efficiency of an SI GaAs PCSS is remarkably enhanced by electric field excursions into the positive resistance region when the total electric field is only below the threshold part of the time.The LSA mode can only operate in the certain conditions that satisfy the quenching of the accumulation layer and the smaller initial domain voltage.
基金Profs.Y.Zhang,J.Chen,J.Zhao,and C.Lin are greatly appreciated.M.Feng thanks financial support from the National Key R&D Program of China(Grant No.2018YFA0305802)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XD30000000)+1 种基金the National Natural Science Foundation of China(Grant Nos.11574364 and 11774267)L.Mao thanks financial support from the National Key R&D Program of China by the Ministry of Science and Technology of China(Grant No.2015C8932400).
文摘The quantum harmonic oscillator(QHO),one of the most important and ubiquitous model systems in quantum mechanics,features equally spaced energy levels or eigenstates.Here we present a new class of nearly ideal QHOs formed by hydrogenic substitutional dopants in an AlGaAs/GaAs heterostructure.On the basis of model calculations,we demonstrate that,when aδ-doping Si donor substitutes the Ga/Al lattice site close to AlGaAs/GaAs heterointerface,a hydrogenic Si QHO,characterized by a restoring Coulomb force producing square law harmonic potential,is formed.This gives rise to QHO states with energy spacing of~8–9 meV.We experimentally confirm this proposal by utilizing gate tuning and measuring QHO states using an aluminum single-electron transistor(SET).A sharp and fast oscillation with period of~7–8 mV appears in addition to the regular Coulomb blockade(CB)oscillation with much larger period,for positive gate biases above 0.5 V.The observation of fast oscillation and its behavior is quantitatively consistent with our theoretical result,manifesting the harmonic motion of electrons from the QHO.Our results might establish a general principle to design,construct and manipulate QHOs in semiconductor heterostructures,opening future possibilities for their quantum applications.
