The compositions of Sr(NO3)2 crystals grown from an aqueous solution doped with Ba^2+ and Pb^2+ were characterized by the electron probe microanalysis technique.It was found that Ba^2+ is enriched in {100} sectors and...The compositions of Sr(NO3)2 crystals grown from an aqueous solution doped with Ba^2+ and Pb^2+ were characterized by the electron probe microanalysis technique.It was found that Ba^2+ is enriched in {100} sectors and Pb^2+ in {111} sectors.The Raman spectra of different parts of these crystals at room temperature in the ranges of 1038-1070cm^-1 and 650-1150cm^-1 were investigated.The results indicated that barium and lead shift the Raman dominating peaks to the lower frequency and broaden the full width at half maximum.Furthermore,barium probably degrades the properties of the Sr(NO3)2 Raman shifter while lead is anticipated to improve it.展开更多
Longitudinal polar modes generate a macroscopic electric field in piezoelectric crystals and cause an additional mechanism of Raman scattering. The classical theory holds that transverse polar modes cannot produce suc...Longitudinal polar modes generate a macroscopic electric field in piezoelectric crystals and cause an additional mechanism of Raman scattering. The classical theory holds that transverse polar modes cannot produce such an additional mechanism. Our quantum theory shows that there is an additional Raman scattering mechanism arising from the electro-optic effect of transverse polar modes.``展开更多
Raman scattering measurements were carried out in self-assembled Ge quantum dot superlattices grown bymolecular beam epitaxy. The characteristics of the Ge-Ge, Si-Ge, Si-SiLoc and Si-Si peaks were investigated,especi...Raman scattering measurements were carried out in self-assembled Ge quantum dot superlattices grown bymolecular beam epitaxy. The characteristics of the Ge-Ge, Si-Ge, Si-SiLoc and Si-Si peaks were investigated,especially the Ge-Ge optical phonon frequency shift was emphasized, which was tuned by the phonon confinementand strain effects. The experimentally observed frequency shift values of the Ge-Ge peak frequency caused byoptical phonon confinement and strain in Ge quantum dots were discussed with quantitative calculations.展开更多
文摘The compositions of Sr(NO3)2 crystals grown from an aqueous solution doped with Ba^2+ and Pb^2+ were characterized by the electron probe microanalysis technique.It was found that Ba^2+ is enriched in {100} sectors and Pb^2+ in {111} sectors.The Raman spectra of different parts of these crystals at room temperature in the ranges of 1038-1070cm^-1 and 650-1150cm^-1 were investigated.The results indicated that barium and lead shift the Raman dominating peaks to the lower frequency and broaden the full width at half maximum.Furthermore,barium probably degrades the properties of the Sr(NO3)2 Raman shifter while lead is anticipated to improve it.
文摘Longitudinal polar modes generate a macroscopic electric field in piezoelectric crystals and cause an additional mechanism of Raman scattering. The classical theory holds that transverse polar modes cannot produce such an additional mechanism. Our quantum theory shows that there is an additional Raman scattering mechanism arising from the electro-optic effect of transverse polar modes.``
文摘Raman scattering measurements were carried out in self-assembled Ge quantum dot superlattices grown bymolecular beam epitaxy. The characteristics of the Ge-Ge, Si-Ge, Si-SiLoc and Si-Si peaks were investigated,especially the Ge-Ge optical phonon frequency shift was emphasized, which was tuned by the phonon confinementand strain effects. The experimentally observed frequency shift values of the Ge-Ge peak frequency caused byoptical phonon confinement and strain in Ge quantum dots were discussed with quantitative calculations.