Low temperature LO-phonon dynamics of MgZnO nanoalloys

In this paper, the authors present research on the low temperature resonant Raman scattering of the LO modes of Mg0.2Zn0.8O nanocrystals. They found that in the LO spectral range, two coupled modes appear: the main LO mode of the alloy and a low frequency mode redshifted by similar to 27 cm(-1) relative to the main one. The low frequency mode was analyzed in terms of three mechanisms applicable to Raman scattering of an alloy system that might result in its activation: phase segregation due to the low solubility limit of the MgO-ZnO alloy system, a convolution of the A1(LO) with the E1(LO) mode, and an order-disorder state. Their analyses indicate that the principle mechanism that activates the low frequency mode is scattering due to the disordered state of the nanoalloys.