Thermal Plasma Synthesis of Crystalline Gallium Nitride Nanopowder from Gallium Nitrate Hydrate and Melamine.

Tae-Hee Kim,Dong-Wha Park,Sooseok Choi

doi:10.3390/nano6030038

Tae-Hee Kim, Dong-Wha Park + Show 1 more

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https://doi.org/10.3390/nano6030038

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Abstract

Gallium nitride (GaN) nanopowder used as a blue fluorescent material was synthesized by using a direct current (DC) non-transferred arc plasma. Gallium nitrate hydrate (Ga(NO3)3∙xH2O) was used as a raw material and NH3 gas was used as a nitridation source. Additionally, melamine (C3H6N6) powder was injected into the plasma flame to prevent the oxidation of gallium to gallium oxide (Ga2O3). Argon thermal plasma was applied to synthesize GaN nanopowder. The synthesized GaN nanopowder by thermal plasma has low crystallinity and purity. It was improved to relatively high crystallinity and purity by annealing. The crystallinity is enhanced by the thermal treatment and the purity was increased by the elimination of residual C3H6N6. The combined process of thermal plasma and annealing was appropriate for synthesizing crystalline GaN nanopowder. The annealing process after the plasma synthesis of GaN nanopowder eliminated residual contamination and enhanced the crystallinity of GaN nanopowder. As a result, crystalline GaN nanopowder which has an average particle size of 30 nm was synthesized by the combination of thermal plasma treatment and annealing.

Highlights

Gallium nitride (GaN) has been used as a binary III–V direct band-gap semiconductor material in light-emitting diodes since the 1990s
GaN nanopowder was synthesized from Ga(NO3 )3 ̈xH2 O (99.9% purity, Alfa Aeser Inc., Boston, MA, USA) and C3 H6 N6
These findings indicate that GaN nanopowder was synthesized from Ga(NO3)3∙32H2O

Summary

Introduction

Gallium nitride (GaN) has been used as a binary III–V direct band-gap semiconductor material in light-emitting diodes since the 1990s. In order to prepare a white light source, blue fluorescence is mixed with other light sources such as yellow, red, or green light. Such white LEDs are taking the place of traditional incandescent and fluorescent lights. Gallium nitride is a very hard material that has a strong atomic bonding as a wurtzite crystal structure It can be used for applications in optoelectronic, high-power, high-frequency, and high temperature devices. GaN can be applied as the substrate which makes violet laser diodes at 405 nm without the requirement of nonlinear optical frequency-doubling It is usually applied by deposition on silicon carbide (SiC) and Nanomaterials 2016, 6, 38; doi:10.3390/nano6030038 www.mdpi.com/journal/nanomaterials

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