Resonance Raman Study of Shell Morphology in InP/ZnSe/ZnS Core/Shell/Shell Nanocrystals

Resonance Raman spectra and absolute cross sections of InP/ZnSe/ZnS core/shell/shell nanocrystals have been obtained at excitation wavelengths 501.7, 457.9, 410 nm. Eight different structures having nearly the same lowest excitonic absorption wavelength but significantly stoichiometries are compared. The show phonon features attributable to both InP core ZnSe shell. largest differences among seen in region by using 457.9 nm, on low-energy edge significant contributions from Here, that stoichiometric (In:P ratio ≈1.0) a sharp, strongly polarized peak near bulk frequency (∼250 cm–1) weak lower-frequency shoulder with higher depolarization ratio. Structures excess indium stronger low-frequency 225 cm–1 lower integrated intensities throughout region. These changes attributed presence atoms results support previous assignment slow rise component time-resolved photoluminescence nonstoichiometric transient trapping holes defects