High‐energy vibrational modes in nitrogen‐doped ZnO

We present results of Raman‐scattering experiments on a series of nitrogen‐doped ZnO epilayers grown by chemical vapor deposition. Nitrogen, a potential acceptor in ZnO, was introduced by the thermal decomposition of ammonia (NH3). We found a structure consisting of at least four lines with frequencies of 2253, 2277, 2291, and 2304 cm–1. They increase in intensity simultaneously with additional modes in the energy range of the host phonons: both scale with the nitrogen concentration in the samples. The origin of the high‐energy structure is tentatively assigned to vibrations of lattice‐bound nitrogen or complexes, composed of the constituents of the dopant NH3. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)