A double-potential-well model is proposed to describe the core-shell thickness-dependent photoluminescence peaks and energy relaxations in semiconductor quantum dots (QDs). The surface effect plays an important role i...A double-potential-well model is proposed to describe the core-shell thickness-dependent photoluminescence peaks and energy relaxations in semiconductor quantum dots (QDs). The surface effect plays an important role in the formation of new states-polaronic states around the surface of QDs. The polaronic states formed emit light due to the strong interaction between the core state (confined state) and the surface state with an enhanced participation of the size effect.展开更多
The emission and Fourier transformation infrared spectra of freshly prepared porous silicon(PS) and the silicon wafer were examined. Increasing temperature generally led to a decrease in the emission intensities of th...The emission and Fourier transformation infrared spectra of freshly prepared porous silicon(PS) and the silicon wafer were examined. Increasing temperature generally led to a decrease in the emission intensities of the PS samples, however, the freshly prepared sample showed an unusually large and sudden increase in its emission intensity at the specific temperature at which the hydrogen ion conductivity in the silicon wafer increased. The O-H vibrations of the silicon wafer also showed a sudden decrease at the same temperature. These results are consistent with the assumption that the luminescence of fresh PS comes from the carrier bound exciton in its confined nanostructure.展开更多
With surface chemical modification,we have obtained core-shell structure ZnO nanoparticles.The nonresonant third-order nonlinear optical refraction of this new composite material was found to be-3.8×10^(-10) esu ...With surface chemical modification,we have obtained core-shell structure ZnO nanoparticles.The nonresonant third-order nonlinear optical refraction of this new composite material was found to be-3.8×10^(-10) esu by Z-scan measurements with a femtosecond pulsed laser.The ultrafast nonlinear response time~250 fs measured by time-resolved pump-probe techniques suggests that the nonlinearity of this new material originates mainly from a rapid electronic polarization process or virtual process such as the optical Stark effect.展开更多
We report the measured results of non-resonant nonlinearity by degenerate four-wave mixing for Cu2O nanopartides having central diameter of 9 nm.The value of x^(3) obtained in a 10ns pulse experiment is 8.48×1O^(...We report the measured results of non-resonant nonlinearity by degenerate four-wave mixing for Cu2O nanopartides having central diameter of 9 nm.The value of x^(3) obtained in a 10ns pulse experiment is 8.48×1O^(-10) esu,and the nonlinear response time of the sample is estimated to be in the order of nanosecond.展开更多
基金Supported by the Bairen Project of the Chinese Academy of Sciences.
文摘A double-potential-well model is proposed to describe the core-shell thickness-dependent photoluminescence peaks and energy relaxations in semiconductor quantum dots (QDs). The surface effect plays an important role in the formation of new states-polaronic states around the surface of QDs. The polaronic states formed emit light due to the strong interaction between the core state (confined state) and the surface state with an enhanced participation of the size effect.
基金Supported by the National Natural Science Foundation of China(No.2 0 1730 73)
文摘The emission and Fourier transformation infrared spectra of freshly prepared porous silicon(PS) and the silicon wafer were examined. Increasing temperature generally led to a decrease in the emission intensities of the PS samples, however, the freshly prepared sample showed an unusually large and sudden increase in its emission intensity at the specific temperature at which the hydrogen ion conductivity in the silicon wafer increased. The O-H vibrations of the silicon wafer also showed a sudden decrease at the same temperature. These results are consistent with the assumption that the luminescence of fresh PS comes from the carrier bound exciton in its confined nanostructure.
文摘With surface chemical modification,we have obtained core-shell structure ZnO nanoparticles.The nonresonant third-order nonlinear optical refraction of this new composite material was found to be-3.8×10^(-10) esu by Z-scan measurements with a femtosecond pulsed laser.The ultrafast nonlinear response time~250 fs measured by time-resolved pump-probe techniques suggests that the nonlinearity of this new material originates mainly from a rapid electronic polarization process or virtual process such as the optical Stark effect.
文摘We report the measured results of non-resonant nonlinearity by degenerate four-wave mixing for Cu2O nanopartides having central diameter of 9 nm.The value of x^(3) obtained in a 10ns pulse experiment is 8.48×1O^(-10) esu,and the nonlinear response time of the sample is estimated to be in the order of nanosecond.