Band gap engineering and spatial confinement of optical phonon in ZnO quantum dots

Both band gap engineering and spatial confinement of optical phonon were observed depending upon the size of ZnO quantum dots at room temperature. Size-dependent blueshifts of photoluminescence and absorption spectra reveal the quantum confinement effect. The measured Raman spectral shift and asymmetry for the E2(high) mode caused by localization of optical phonons agree well with that calculated by using the modified spatial correlation model.