The electromagnetic interaction between Ag nanoparticles on the top of the Si substrate and the incident light has been studied by numerical simulations. It is found that the presence of dielectric layers with differe...The electromagnetic interaction between Ag nanoparticles on the top of the Si substrate and the incident light has been studied by numerical simulations. It is found that the presence of dielectric layers with different thicknesses leads to the varied resonance wavelength and scattering cross section and consequently the shifted photocurrent response for all wavelengths. These different behaviours are determined by whether the dielectric layer is beyond the domain where the elcetric field of metallic plasmons takes effect, combined with the effect of geometrical optics. It is revealed that for particles of a certain size, an appropriate dielectric thickness is desirable to achieve the best absorption. For a certain thickness of spacer, an appropriate granular size is also desirable. These observations have substantial applications for the optimization of surface plasmon enhanced silicon solar cells.展开更多
Double-peak N-shaped negative differential resistance(NDR)with a high peak-to-valley ratio is observed in the output characteristics of a GaAs-based modulation-doped field effect transistor with InAs quantum dots in t...Double-peak N-shaped negative differential resistance(NDR)with a high peak-to-valley ratio is observed in the output characteristics of a GaAs-based modulation-doped field effect transistor with InAs quantum dots in the barrier layer(QDFET).One NDR peak with a higher source-drain voltage VDS is explained as the real-space transfer(RST)of high-mobility electrons in the channel into the quantum dots layer,while the other with a lower VDS is caused by the high-mobility RST electrons in the channel into the modulation-doped AlGaAs barrier layer on the other side.We depict a point how a thinner Schottky barrier layer provides a stronger potential,opening a possibility of two-directional channel electron transfer when a much higher VG is applied.The result suggests that the QDFET can be an attractive candidate for high-speed logic application and memory devices.展开更多
基金supported by the National Basic Research Program of China (Grant Nos.2010CB934104 and 2010CB933800)the National Natural Science Foundation of China (Grant Nos.60606024 and 61076077)
文摘The electromagnetic interaction between Ag nanoparticles on the top of the Si substrate and the incident light has been studied by numerical simulations. It is found that the presence of dielectric layers with different thicknesses leads to the varied resonance wavelength and scattering cross section and consequently the shifted photocurrent response for all wavelengths. These different behaviours are determined by whether the dielectric layer is beyond the domain where the elcetric field of metallic plasmons takes effect, combined with the effect of geometrical optics. It is revealed that for particles of a certain size, an appropriate dielectric thickness is desirable to achieve the best absorption. For a certain thickness of spacer, an appropriate granular size is also desirable. These observations have substantial applications for the optimization of surface plasmon enhanced silicon solar cells.
基金Supported by the National Basic Research Program of China(973 Program)under Grant No 2010CB934104the National Natural Science Foundation of China under Grant Nos 60606024 and 61076077.
文摘Double-peak N-shaped negative differential resistance(NDR)with a high peak-to-valley ratio is observed in the output characteristics of a GaAs-based modulation-doped field effect transistor with InAs quantum dots in the barrier layer(QDFET).One NDR peak with a higher source-drain voltage VDS is explained as the real-space transfer(RST)of high-mobility electrons in the channel into the quantum dots layer,while the other with a lower VDS is caused by the high-mobility RST electrons in the channel into the modulation-doped AlGaAs barrier layer on the other side.We depict a point how a thinner Schottky barrier layer provides a stronger potential,opening a possibility of two-directional channel electron transfer when a much higher VG is applied.The result suggests that the QDFET can be an attractive candidate for high-speed logic application and memory devices.
