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In Dy 3+ and Li + codoped ZnO nanowires, the additives accumulate preferentially in {0001} planes, resulting in serious breakdown of the translational symmetry in ab plane and modification of the phonon oscillation field. Not only acoustic overtones, silent optical modes, surface optical (SO) phonon modes, and multi-phonon processes can be effectively observed in the nonresonant Raman scattering (RS) and the Fourier-transform infrared (FTIR) spectra, but the quasi-LO and TO modes of mixed A 1 and E 1 symmetry also show a noticeable red shift from E 1 symmetry (in ab plane) to A 1 symmetry (along c axis). The presence of dislocations and internal strain at the surface layer rich in additives, coming from the segregation of additives, forms a quasi-bilayer system, resulting in the appearance and enhancement of SO phonon modes in RS and FTIR spectra. The Fano interference, originating from the interaction between the discrete scattering from phonons and the continuum scattering from laser-induced electrons in the doped nanostructures, leads to typical asymmetric lineshapes on the lower wavenumber sides.

Hierarchical heterostructures of zinc antimonate nanoislands on ZnO nanobelts were prepared by simple annealing of the polymeric precursor. Sb can promote the growth of ZnO nanobelts along the [552] direction because of the segregation of Sb dopants on the +(001) and (110) surfaces of ZnO nanobelts. Furthermore, the ordered nanoislands of toothlike ZnSb2O6 along the [001]ZnO direction and rodlike Zn7Sb2O12 along the [110]ZnO direction can be formed because of the match relation of the lattice and polar charges between ZnO and zinc antimonate. The incorporation of Sb in a ZnO lattice induces composition fluctuation, and the growth of zinc antimonate nanoislands on nanobelt sides induces interface fluctuation, resulting in dominance of the bound exciton transition in the room temperature near-band-edge (NBE) emission at relatively low excitation intensity. At high excitation intensity, however, Auger recombination makes photogenerated electrons release phonon and relax from the conduction band to the trap states, causing the NBE emission to gradually saturate and redshift with increasing excitation intensity. The green emission more reasonably originates from the recombination of electrons in shallow traps with doubly charged V O * * oxygen vacancies. Because a V O * * center can trap a photoactivated electron and change to a singly charged oxygen vacancy V O * state, its emission intensity exhibits a maximum with increasing excitation intensity.