A resonant cavity-enhanced （RCE） quantum dot （QD） field-effect transistor （RCEQDFET） is designed for single- photon detection in this paper. Adding distributed Bragg reflection （DBR） mirrors to the single-phot...A resonant cavity-enhanced （RCE） quantum dot （QD） field-effect transistor （RCEQDFET） is designed for single- photon detection in this paper. Adding distributed Bragg reflection （DBR） mirrors to the single-photon detector （SPD）, we improve the light absorption efficiency of the SPD. The effects of the reflectivity of the mirrors, the thickness and light absorption coefficient of the absorbing layer on the detector＇s light absorption efficiency are investigated, and the resonant cavity is determined by using the air/semiconductor interface as the mirror on the top. Through analyzing the relationship between the refractive index of AlxGal_xAs and A1 component, we choose A1As/Alo.15Gao.85As as the material of the mirror on the bottom. The pairs of A1As/Alo.15Gao.85As film are further determined to be 21 by calculating the reflectivity of the mirror. The detector is fabricated from semiconductor heterostructures grown by molecular beam epitaxy. The reflection spectrum, photoluminescence （PL） spectrum, photocurrent response, and channel current of the detector are tested and the results show that the RCEQDFET-SPD designed in this paper has better performances in photonic response and wavelength selection.展开更多
The emergence of light-tunable synaptic transistors provides opportunities to break through the von Neumann bottleneck and enable neuromorphic computing.Herein,a multifunctional synaptic transistor is constructed by u...The emergence of light-tunable synaptic transistors provides opportunities to break through the von Neumann bottleneck and enable neuromorphic computing.Herein,a multifunctional synaptic transistor is constructed by using 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene(C8-BTBT)and indium gallium arsenide(InGaAs)nanowires(NWs)hybrid heterojunction thin film as the active layer.Under illumination,the Type-I C8-BTBT/InGaAs NWs heterojunction would make the dissociated photogenerated excitons more difficult to recombine.The persistent photoconductivity caused by charge trapping can then be used to mimic photosynaptic behaviors,including excitatory postsynaptic current,long/short-term memory and Pavlovian learning.Furthermore,a high classification accuracy of 89.72%can be achieved through the single-layer-perceptron hardware-based neural network built from C8-BTBT/InGaAs NWs synaptic transistors.Thus,this work could provide new insights into the fabrication of high-performance optoelectronic synaptic devices.展开更多
Feshbach resonance is a resonance for two-atom scattering with two or more channels,in which a bound state is achieved in one channel.We show that this resonance phenomenon not only exists during the collisions of mas...Feshbach resonance is a resonance for two-atom scattering with two or more channels,in which a bound state is achieved in one channel.We show that this resonance phenomenon not only exists during the collisions of massive particles,but also emerges during the coherent transport of massless particles,that is,photons confined in the coupled resonator arrays linked by a separated cavity or a tunable two level system(TLS).When the TLS is coupled to one array to form a bound state in this setup,the vanishing transmission appears to display the photonic Feshbach resonance.This process can be realized through various experimentally feasible solid state systems,such as the couple defected cavities in photonic crystals and the superconducting qubit coupled to the transmission line.The numerical simulation based on the finite-different time-domain(FDTD) method confirms our assumption about the physical implementation.展开更多
In this paper, we propose an on-chip all optical transistor driven by optical gradient force. The transistor consists of a single micro-ring resonator, half of which is suspended from the substrate, and a bus waveguid...In this paper, we propose an on-chip all optical transistor driven by optical gradient force. The transistor consists of a single micro-ring resonator, half of which is suspended from the substrate, and a bus waveguide. The free-standing arc is bent by optical gradient force generated when the control light is coupled into the ring. The output power of the probe light is tuned continuously as the transmission spectrum red-shift due to the displacement of the free-standing arc. The transistor shows three working regions known as cutoff region, amplified region and saturate region, and the characteristic curve is tunable by changing the wavelength of the control light. Potential applications of the all optical transistor include waveform regeneration and other optical computing.展开更多
设计了一种基于场效应晶体管的量子点场效应单光子探测器(quantum dot field effect transistor,QDFET),建立了二维电子气(two-dimensional electron gas,2DEG)的薛定谔方程和泊松方程,通过对薛定谔方程和泊松方程的自洽求解,对2DEG的...设计了一种基于场效应晶体管的量子点场效应单光子探测器(quantum dot field effect transistor,QDFET),建立了二维电子气(two-dimensional electron gas,2DEG)的薛定谔方程和泊松方程,通过对薛定谔方程和泊松方程的自洽求解,对2DEG的载流子浓度进行了模拟。模拟结果显示,AlGaAs的Al组分、δ掺杂层的掺杂浓度以及隔离层的厚度对于2DEG的载流子浓度均有影响。为了使2DEG具有较高的载流子浓度,AlGaAs的Al组分应为0.2~0.4,δ掺杂浓度应为6~8×10^(13)/cm^2,隔离层厚度应在50nm以下。通过对2DEG的载流子浓度进行研究,可以掌握2DEG载流子浓度的影响因素,从而通过优化QDFET结构,可提高2DEG的载流子浓度。这对于高灵敏度QDFET的制备具有重要的意义和应用价值。展开更多
We demonstrate a wireless transmission link at 3.9 THz over a distance of 0.5 m by employing a terahertz （Hz） quantum-cascade laser （QCL） and a THz quantum-well photodetector （QWP）. We make direct voltage modula...We demonstrate a wireless transmission link at 3.9 THz over a distance of 0.5 m by employing a terahertz （Hz） quantum-cascade laser （QCL） and a THz quantum-well photodetector （QWP）. We make direct voltage modulation of the THz QCL and use a spectral-matched THz QWP to detect the modulated THz light from the laser. The small signal model and a direct voltage modulation scheme of the laser are presented. A square wave up to 30 MHz is added to the laser and detected by the THz detector. The bandwidth limit of the wireless link is also discussed.展开更多
Pockel＇s effect and optical rectification induced by the built-in electric field in the space charge region of a silicon surface layer are demonstrated in a {001}-cut high-resistance silicon crystal. The half-wave vo...Pockel＇s effect and optical rectification induced by the built-in electric field in the space charge region of a silicon surface layer are demonstrated in a {001}-cut high-resistance silicon crystal. The half-wave voltage is about 203 V, deduced by Pockel＇s effect. The ratio Xzzz^（2）/X^（2）zzz） is calculated to be about 0.942 according to optical rectification. Our comparison with the Kerr signal shows that Pockel＇s signal is much stronger. This indicates that these effects are so considerable that they should be taken into account when designing silicon-based photonic devices.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.61274125)the Natural Science Foundation of Beijing,China(Grant No.11DB1262)
文摘A resonant cavity-enhanced （RCE） quantum dot （QD） field-effect transistor （RCEQDFET） is designed for single- photon detection in this paper. Adding distributed Bragg reflection （DBR） mirrors to the single-photon detector （SPD）, we improve the light absorption efficiency of the SPD. The effects of the reflectivity of the mirrors, the thickness and light absorption coefficient of the absorbing layer on the detector＇s light absorption efficiency are investigated, and the resonant cavity is determined by using the air/semiconductor interface as the mirror on the top. Through analyzing the relationship between the refractive index of AlxGal_xAs and A1 component, we choose A1As/Alo.15Gao.85As as the material of the mirror on the bottom. The pairs of A1As/Alo.15Gao.85As film are further determined to be 21 by calculating the reflectivity of the mirror. The detector is fabricated from semiconductor heterostructures grown by molecular beam epitaxy. The reflection spectrum, photoluminescence （PL） spectrum, photocurrent response, and channel current of the detector are tested and the results show that the RCEQDFET-SPD designed in this paper has better performances in photonic response and wavelength selection.
基金This work is supported by the National Natural Science Foundation of China(No 52173192 and No 61975241)the Huxiang Youth Talent Program of Hunan Province(2020RC3010)+3 种基金the Science and Technology Innovation Program of Hunan Province(2020RC4004)the Special Funding for the Construction of Innovative Provinces in Hunan Province(2020GK2024)the National Key Research and Development Program of China(2017YFA0206600)P.X.also thanks a fellowship award from the Research Grants Council of the Hong Kong Special Administrative Region,China(CityU RFS2021-1S04).
文摘The emergence of light-tunable synaptic transistors provides opportunities to break through the von Neumann bottleneck and enable neuromorphic computing.Herein,a multifunctional synaptic transistor is constructed by using 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene(C8-BTBT)and indium gallium arsenide(InGaAs)nanowires(NWs)hybrid heterojunction thin film as the active layer.Under illumination,the Type-I C8-BTBT/InGaAs NWs heterojunction would make the dissociated photogenerated excitons more difficult to recombine.The persistent photoconductivity caused by charge trapping can then be used to mimic photosynaptic behaviors,including excitatory postsynaptic current,long/short-term memory and Pavlovian learning.Furthermore,a high classification accuracy of 89.72%can be achieved through the single-layer-perceptron hardware-based neural network built from C8-BTBT/InGaAs NWs synaptic transistors.Thus,this work could provide new insights into the fabrication of high-performance optoelectronic synaptic devices.
基金supported by the National Natural Science Foundation of China (Grant Nos.10474104,60433050 and10704023)the National Basic Research Program of China (Grant Nos.2006CB921205 and 2005CB724508)
文摘Feshbach resonance is a resonance for two-atom scattering with two or more channels,in which a bound state is achieved in one channel.We show that this resonance phenomenon not only exists during the collisions of massive particles,but also emerges during the coherent transport of massless particles,that is,photons confined in the coupled resonator arrays linked by a separated cavity or a tunable two level system(TLS).When the TLS is coupled to one array to form a bound state in this setup,the vanishing transmission appears to display the photonic Feshbach resonance.This process can be realized through various experimentally feasible solid state systems,such as the couple defected cavities in photonic crystals and the superconducting qubit coupled to the transmission line.The numerical simulation based on the finite-different time-domain(FDTD) method confirms our assumption about the physical implementation.
基金Acknowledgements This work was partially supported by the Program for New Century Excellent Talents in Ministry of Education of China （No. NCET-11-0168）, and the National Natural Science Foundation of China （Grant Nos. 11174096 and 61475052）.
文摘In this paper, we propose an on-chip all optical transistor driven by optical gradient force. The transistor consists of a single micro-ring resonator, half of which is suspended from the substrate, and a bus waveguide. The free-standing arc is bent by optical gradient force generated when the control light is coupled into the ring. The output power of the probe light is tuned continuously as the transmission spectrum red-shift due to the displacement of the free-standing arc. The transistor shows three working regions known as cutoff region, amplified region and saturate region, and the characteristic curve is tunable by changing the wavelength of the control light. Potential applications of the all optical transistor include waveform regeneration and other optical computing.
文摘设计了一种基于场效应晶体管的量子点场效应单光子探测器(quantum dot field effect transistor,QDFET),建立了二维电子气(two-dimensional electron gas,2DEG)的薛定谔方程和泊松方程,通过对薛定谔方程和泊松方程的自洽求解,对2DEG的载流子浓度进行了模拟。模拟结果显示,AlGaAs的Al组分、δ掺杂层的掺杂浓度以及隔离层的厚度对于2DEG的载流子浓度均有影响。为了使2DEG具有较高的载流子浓度,AlGaAs的Al组分应为0.2~0.4,δ掺杂浓度应为6~8×10^(13)/cm^2,隔离层厚度应在50nm以下。通过对2DEG的载流子浓度进行研究,可以掌握2DEG载流子浓度的影响因素,从而通过优化QDFET结构,可提高2DEG的载流子浓度。这对于高灵敏度QDFET的制备具有重要的意义和应用价值。
基金supported by the Ministry of Science and Technology of the People’s Republic of China(2018YFA0703200)the National Natural Science Foundation of China(91833306,51633006,51703160,51733004,51725304,and 52003189)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZZ130 and 2021ZZ129)。
基金supported by the National 973 Program of China(No.2014CB339803)the National 863 Program of China(No.2011AA010205)+4 种基金the National Natural Science Foundation of China(Nos.61131006,61321492,61176086,61204135,and 61306066)the Major National Development Project of Scientific Instrument and Equipment(No.2011YQ150021)the National Science and Technology Major Project(No.2011ZX02707)the Major Project(No.YYYJ1123-1)the International Collaboration and Innovation Program on High Mobility Materials Engineering of the Chinese Academy of Sciences and the Shanghai Municipal Commission of Science and Technology(No.13ZR1464600)
文摘We demonstrate a wireless transmission link at 3.9 THz over a distance of 0.5 m by employing a terahertz （Hz） quantum-cascade laser （QCL） and a THz quantum-well photodetector （QWP）. We make direct voltage modulation of the THz QCL and use a spectral-matched THz QWP to detect the modulated THz light from the laser. The small signal model and a direct voltage modulation scheme of the laser are presented. A square wave up to 30 MHz is added to the laser and detected by the THz detector. The bandwidth limit of the wireless link is also discussed.
基金supported by the National Natural Science Foundation of China (Nos. 61474055 and 60976043)the National 863 Program of China (No. 2009AA03Z419)
文摘Pockel＇s effect and optical rectification induced by the built-in electric field in the space charge region of a silicon surface layer are demonstrated in a {001}-cut high-resistance silicon crystal. The half-wave voltage is about 203 V, deduced by Pockel＇s effect. The ratio Xzzz^（2）/X^（2）zzz） is calculated to be about 0.942 according to optical rectification. Our comparison with the Kerr signal shows that Pockel＇s signal is much stronger. This indicates that these effects are so considerable that they should be taken into account when designing silicon-based photonic devices.
