Rapid synthesis of high purity GaN powder

Abstract

High purity, strong luminescent gallium nitride (GaN) powders were synthesized by direct reaction of gallium (Ga) and ammonia (NH 3 ) using bismuth (Bi) as a catalyst in a vertical furnace. The reaction rate and yield from metal Ga were improved dramatically in the presence of Bi. In this simple apparatus, 25g Ga can be fully, stoichiometrically converted into GaN within 5 hours. The optimum temperature, NH 3 flow rate and reaction time in this hot wall tube furnace were 1000 o C, 500 standard cubic centimetres per minute (sccm) and 5 hours, respectively. X-ray diffraction demonstrates that the material has a high purity and a single crystalline structure. Electron microscopy was used to characterize the morphology of the powder particles. Powder purity was analyzed by utilizing Glow Discharge Mass Spectrometry (GDMS). Cathodoluminescence (CL) data showed strong luminescence from the powder.

Distributions of Conduction Electrons as Manifested in MAS NMR of Gallium Nitride

“…The full spectrum including ±1/2 ↔ ±3/2 satellite transitions of the sample prepared using a Na/K flux has been given previously, along with chemical shift referencing, assignments of a minor component from the cubic polytype and spinning sidebands (seen as minor bumps in all three spectra), and additional characterization. Two of the samples were prepared by a new synthetic procedure reacting Ga metal with NH 3 in the presence of Bi catalyst in boats made of either quartz or BN. All samples, especially the two made with Bi catalyst, exhibit a broad structureless absorption on the high frequency (left) side of the main h-GaN peak.…”

Study on the sublimation growth of GaN using different powder sources and investigation on the sublimation behaviour of GaN powder by means of thermogravimetry

“…3 Results and discussion Some earlier experiments showed that the crystal quality obtained from sublimation growth using commercially available GaN powders are not satisfying which was also reported by Wu et al [5]. Those commercial powders have a yellowish colour and an oxygen content in the range of some percent.…”

Vapor phase growth of GaN using GaN powder sources and thermogravimetric investigations of the evaporating behaviour of the source material

“…One key question in GaN vapor phase growth is whether GaN powder or liquid gallium should be provided as source material. In case of using a GaN powder source for the vapor phase growth the quality and purity of the GaN source material is very important [2]. Therefore, thermogravimetric (TG) measurements are used to investigate the evaporation behaviour of GaN powders.…”