Gallium nitride powders: Mechanism of ammonothermal synthesis, ball-mill assisted rare earth doping and uniform electrophoretic deposition
✍ Scribed by Tiju Thomas; Xiaomei Guo; Junxia Shi; Lori A. Lepak; M.V.S. Chandrashekhar; Kewen Li; Francis J. DiSalvo; Michael G. Spencer
- Publisher
- Elsevier Science
- Year
- 2011
- Tongue
- English
- Weight
- 966 KB
- Volume
- 316
- Category
- Article
- ISSN
- 0022-0248
No coin nor oath required. For personal study only.
✦ Synopsis
Based on free molecular flow analysis and powder growth experiments, we present evidence that ammonothermal synthesis of GaN powders is primarily a liquid phase process. Rare earth doped GaN nanopaticles were synthesized from as-prepared GaN using a ball-mill assisted solid state reaction. The ball-milled powders were heat treated under different conditions to facilitate dopant diffusion. Luminescence properties of the rare earth doped GaN powders in the near infrared regime were investigated using a photoluminescence (PL) apparatus. The maximum PL at 1.55 mm (C band) was obtained from Er/Tb co-doped GaN annealed in air at 923 K for 4 h. The nanosized GaN particles was then uniformly deposited on a suitably prepared glass substrate using a home built electrophoretic set. A suspension of ethanol, glycerol, Mg(NO 3 ) 2 and nanosized GaN was used in the electrophoretic bath. Use of electric fields in the range 80-100 V cm À 1 and constant current density of $ 1.60 mA cm À 2 gave uniform and complete coverage of GaN on the substrate.