Thermal analysis of GaN powder formation via reaction of gallium ethylenediamine tetraacetic acid complexes with ammonia

Abstract

AbstractThe reaction mechanism of gallium ethylenediamine tetraacetic acid (Ga[(OOCCH2)2–N–CH2–CH2–N–(CH2COO)2]NH4) (Ga‐EDTA)with ammonia was investigated. The Ga‐EDTA·NH4 complex powders were analyzed by thermogravimetric and differential thermal analysis (TG/DTA) under flow of ammonia gas and nitrogen gas. From the TG/DTA results, it is shown that the precursors undergo a sharp mass loss at about 296 °C (step I) due to the release of organic groups, followed by further releasing of organic groups (297∼ 552 °C, step II), elimination of carbon and formation of GaN (552 ∼ 650 °C, step III), GaN crystallization and further elimination of carbon (650 ∼ 850 °C, step IV), the improvement of GaN crystal quality (600 ∼ 1100 °C, step‐IV) and the initial decomposition of GaN powders. The X‐ray diffraction analysis of the powders indicates that proper sintering temperature for GaN powders should be approximate to 1100 °C. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)