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

Abstract

Using 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)

Crystal field and Zeeman parameters of substitutional Yb3+ ion in GaN

“…The high thermal conductivity, chemical and thermal stability, refractive index, breakdown dielectric strength and wide band gaps of GaN, AlN and their alloys create opportunities to explore the spectral characteristics of RE 3+ ions in a wide spectral range. It was shown recently that efficient phosphors [1][2][3], optically stimulated laser action [4] and electrically excited p-n junction light emitting diode [5] are feasible using these materials. Despite of these recent technological advances the electronic structure of the RE luminescence centers, as well as their indirect excitation mechanism are still not well understood.…”

Rare earth 4f hybridization with the GaN valence band

“…In recent decades, rare earth (RE)-doped semiconductors have generated interest due to their applications in new optoelectronic devices [1][2][3][4]. III-nitride semiconductors, such as AlN, GaN and InN offer tunable band gaps and favorable thermal, chemical and electronic properties, which facilitate various device applications [5][6][7][8][9] from the ultraviolet through the visible and the infrared range. Moreover, thin film electroluminescent phosphors with red, blue, and green emissions [7][8][9][10][11][12][13][14] imply the promise of full color (white) light capability.…”

Schottky barrier formation at the Au to rare earth doped GaN thin film interface

“…Moreover, the tunable band gaps of these III-nitride alloys offer device applications across the visible spectrum through the ultraviolet range, to include optically stimulated lasing [5] and p-n junction light-emitting diodes in the red [6] using lanthanide-doped AlN and GaN, as well as in the blue. Lastly, the production of thin film electroluminescent phosphors with red, blue, and green emissions [7][8][9] offers the promise of full color (white) light capability.…”