Synthesis of N-deficient GaN and its enhanced dielectric responses

The GaN powders were synthesized by the reaction of Ga2O3 and Li3N and scanning transmission electron microscopy (STEM) analysis showed the as-prepared GaN were N-deficient with the N vacancies reaching as much as 21 %. Besides single-phase of the hexagonal GaN, no other phase from impurities can be detected under the high-resolution transmission electron microscopy (HRTEM) observations. The room temperature (RT) frequency spectrums of the relative dielectric constants 8, were measured and the N-deficient GaN exhibited at least twofold enhancement than that of GaN nanostructure materials, especially at low frequency range. Because of the great number of N vacancies (V-N), the rotation direction polarization (RDP) contributes mostly for the enhancement of epsilon(r) in N-deficient GaN. (C) 2007 Elsevier B.V. All rights reserved.