Synthesis of rare‐earth activated AlN and GaN powders via a three‐step conversion process

Abstract

AbstractUsing a three‐step solution method, we have successfully synthesized rare‐earth (RE) activated AlN, GaN, and pure GaAlN powders. Aluminium and/or gallium nitrates are first dissolved in water. For AlN:RE, rare‐earth nitrates converted from their corresponding oxides of Dy3+ and Tm3+ are then added to the precursor nitrate solution. The mixture is subsequently converted into Al(OH)3:RE by combining with aqueous NH4OH at room temperature. The product is then mixed with aqueous NH4F to form (NH4)3AlF6:RE. The conversion process is complete when the hexafluoride compound is flushed with anhydrous ammonia to produce the final nitride product AlN:Dy3+,Tm3+. GaN, GaN:Tb3+ and GaAlN are synthesized similarly. Single phase, pure GaN and GaAlN formation has been confirmed. Dysprosium oxide has been observed in AlN:Dy3+, Tm3+. Oxygen concentration of approximately 4 at% has been measured in GaN powders, and is slightly higher in AlN powders. Spectroscopic measurements show clearly observable emission from Dy3+ and Tm3+ co‐activated AlN samples. In activated GaN samples, Tb3+ emission has been observed. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)