InAs quantum dots are introduced into resonant tunneling diodes to study the electronic transport behavior,and a wide bistability(ΔV~0.8 V)is observed in the negative differential resistance region.Based on an analyt...InAs quantum dots are introduced into resonant tunneling diodes to study the electronic transport behavior,and a wide bistability(ΔV~0.8 V)is observed in the negative differential resistance region.Based on an analytic model,we attribute the observed distinct bistability of a resonant tunneling diodes with quantum dots to the feedback dependence of energy of the electron-storing quantum dots on the tunneling current density.Meanwhile,we find that this wide bistable region can be modulated sensitively by light illumination and becomes narrower with increasing light intensity.Our results suggest that the present devices can be potentially used as sensitive photodetectors in optoelectronic fields.展开更多
We report that a metal-dielectric-metal cavity with a perforated top metallic filn shows a remarkable polarizationselective collimation effect through reflection on the perforated film.According to simulations,such pl...We report that a metal-dielectric-metal cavity with a perforated top metallic filn shows a remarkable polarizationselective collimation effect through reflection on the perforated film.According to simulations,such plasmonic cavities can achieve nearly perfect absorption (R<1.5%) of a transverse magnetic (TM) wave at an optimized incident angle while nearly perfect reflection (R~100%) at normal incidence.A very wide incident angle range (approximately 15°-65°) is found to exhibit a high absorption ratio exceeding over 70%.In contrast,for a transverse electric (TE) wave,the plasmonic cavities remain highly reflective (R~100%) regardless of the incident angles.We elucidate that this polarization- and angle-dependent behavior arises from an even-order (N =2) horizontal Fabry-Perot (FP) resonant mode inside the plasmonic cavity.This effect may find potential applications for angle filtering of polarized divergent light beams in optics.展开更多
Au/GaAs/Au plasmonic cavities with a periodic hole array perforated in the top Au layer are studied.Propagating surface plasmons(PSPs)and localized surface plasmons(LSPs)associated with the rectangle hole shapes are f...Au/GaAs/Au plasmonic cavities with a periodic hole array perforated in the top Au layer are studied.Propagating surface plasmons(PSPs)and localized surface plasmons(LSPs)associated with the rectangle hole shapes are found to interact and highly hybridize in the cavity structure,which eventually determines the resonance properties of the cavities.An anticrossing of resonance frequencies in the reflection spectra is observed when the frequency of PSPs approaches that of LSPs,demonstrating the strong coupling between SPPs and LSPs in the tri-layer plasmonic cavities.This work may provide hints to the plasmonic cavity design for light-harvesting optoelectronic applications.展开更多
The gas gain and energy resolution of single and double THGEM detectors （5 cm×5 cm effective area） with mini-rims （rim less than 10 um） were studied. The maximum gain was found to reach 5×103 and 2 ×...The gas gain and energy resolution of single and double THGEM detectors （5 cm×5 cm effective area） with mini-rims （rim less than 10 um） were studied. The maximum gain was found to reach 5×103 and 2 × 105 for single and double THGEMs respectively, while the energy resolution for 5.9 keV X-rays varied from 18% to 28% for both single and double THGEM detectors of different hole sizes and thicknesses. Different combinations were also investigated of noble gases （argon, neon） mixed with a quantity of other gases （isobutane, methane） at atmospheric pressure.展开更多
基金the National Basic Research Program of China Grant Nos 2011CB925600/2009CB929300the National Natural Science Foundation of China under Grant No 10990100Shanghai Science and Technology Committee under Contract No 09dj1400100.
文摘InAs quantum dots are introduced into resonant tunneling diodes to study the electronic transport behavior,and a wide bistability(ΔV~0.8 V)is observed in the negative differential resistance region.Based on an analytic model,we attribute the observed distinct bistability of a resonant tunneling diodes with quantum dots to the feedback dependence of energy of the electron-storing quantum dots on the tunneling current density.Meanwhile,we find that this wide bistable region can be modulated sensitively by light illumination and becomes narrower with increasing light intensity.Our results suggest that the present devices can be potentially used as sensitive photodetectors in optoelectronic fields.
基金Supported by the National Basic Research Program of China Grant No 2009CB929300the National Natural Science Foundation of China under Grant Nos 10804019,11174055 and 11174057,Shanghai Science and Technology Committee(No 09dj1400103).
文摘We report that a metal-dielectric-metal cavity with a perforated top metallic filn shows a remarkable polarizationselective collimation effect through reflection on the perforated film.According to simulations,such plasmonic cavities can achieve nearly perfect absorption (R<1.5%) of a transverse magnetic (TM) wave at an optimized incident angle while nearly perfect reflection (R~100%) at normal incidence.A very wide incident angle range (approximately 15°-65°) is found to exhibit a high absorption ratio exceeding over 70%.In contrast,for a transverse electric (TE) wave,the plasmonic cavities remain highly reflective (R~100%) regardless of the incident angles.We elucidate that this polarization- and angle-dependent behavior arises from an even-order (N =2) horizontal Fabry-Perot (FP) resonant mode inside the plasmonic cavity.This effect may find potential applications for angle filtering of polarized divergent light beams in optics.
基金by the National Basic Research Program of China under Grant No 2009CB929300the National Natural Science Foundation of China under Grant Nos 60725417,10804019 and 60990321+1 种基金Shanghai Science and Technology Committee under Grant Nos 08dj1400302 and 09dj1400103Japan Science and Technology Corporation(JST)Project.
文摘Au/GaAs/Au plasmonic cavities with a periodic hole array perforated in the top Au layer are studied.Propagating surface plasmons(PSPs)and localized surface plasmons(LSPs)associated with the rectangle hole shapes are found to interact and highly hybridize in the cavity structure,which eventually determines the resonance properties of the cavities.An anticrossing of resonance frequencies in the reflection spectra is observed when the frequency of PSPs approaches that of LSPs,demonstrating the strong coupling between SPPs and LSPs in the tri-layer plasmonic cavities.This work may provide hints to the plasmonic cavity design for light-harvesting optoelectronic applications.
基金Supported by Youth Fund of Institute of High Energy PhysicsChinese Academy of Sciences and National Natural Science Foundation of China (10775151)
文摘The gas gain and energy resolution of single and double THGEM detectors （5 cm×5 cm effective area） with mini-rims （rim less than 10 um） were studied. The maximum gain was found to reach 5×103 and 2 × 105 for single and double THGEMs respectively, while the energy resolution for 5.9 keV X-rays varied from 18% to 28% for both single and double THGEM detectors of different hole sizes and thicknesses. Different combinations were also investigated of noble gases （argon, neon） mixed with a quantity of other gases （isobutane, methane） at atmospheric pressure.
