Temperature-dependent Raman scattering in N–In codoped p-type ZnO thin films

We have carried out a detailed temperature-dependent Raman scattering investigation on coupled longitudinal-optical phonon-plasmon modes in N-In codoped p-type ZnO thin films with different hole densities. In combination with the theoretical analysis for the temperature-dependent frequencies, linewidths, and lifetimes, we have revealed an asymmetrical decay process with frequencies near 450 and 130 cm-1, an increasing anharmonic effect with hole density, as well as a decreasing lifetime with enhanced anharmonicity. The variation in the relative contribution from three- and four-phonon processes can be further attributed to the diversification of the local phonon density of states due to N-In codoping.