Abstract

A complete description of the first‐order Raman and Brillouin spectra of single‐crystal aluminum nitride is provided. The frequency has been measured and the symmetry identified of each of the Raman‐active zone‐center optic modes, and the five independent elastic constants have been measured. The widths of the principal Raman modes increase with increasing oxygen content up to a critical value of approximately 1 at.%, after which they are constant. This behavior supports the hypothesis of a change in the nature of the oxygen defect at that concentration.