Resonant Raman scattering in hydrogen and nitrogen doped ZnO

Raman backscattering measurements were performed on single crystal ZnO for different excitation wavelengths before and after ion implantation with hydrogen and nitrogen. In addition to the formation of H- and N-related defects due to implantation, anomalous Raman modes were observed. Recently, the anomalous Raman modes have been attributed to the disorder-induced activation of silent modes. However, we will show that part of the observed modes are due to the resonantly enhanced longitudinal optical phonons.