Abstract
GaN micro-crystals were synthesized through the direct reaction of $NH_3$with a Ga-melt. The bubbling technique in the atmospheric $NH_3$ ambient was employed and dark-gray-colored GaN micro-crystals with various sizes ranging from 0.5~30$\mu \textrm{m}$ were obtained. It was confirmed that product yield increased with increasing reaction temperature. The synthesized GaN micro-crystals were characterized by using a particle size analyzer, SEM, XRD and PL. The variation of reaction temperature from $850^{\circ}C$ to $1150^{\circ}C$ result in morphological change and in optical characteristics of GaN micro-crystals. Especially; GaN micro-crystals synthesized at 10sec showed the highest crystallinity and low yellow band luminescence.
Ga-melt내에서 $NH_3$기체를 직접 반응시켜 GaN미세결정을 합성하였다. 약 1기압의 NH$_3$기체 분위기에서 bubbling을 적용하였고, 0.5~30$\mu \textrm{m}$ 크기의 진회색의 GaN 미세결정을 합성하였다. 또한, 반응 온도를 증가시켰을 때 반응 수율이 증가함을 확인하였다. 합성된 GiN미세결정을 입도분석, SEM, XRD 및 PL측정 등으로 결정성을 분석하였다. 합성된 GaN미세결정은 850~$1150^{\circ}C$의 반응온도 변화에 따라 결정 형태와 광학적 특성이 변화함을 확인하였다. 특히, $1050^{\circ}C$에서 합성된 GaN미세결정이 결정성이 우수하고, yellow band omission이 낮게 나타남을 확인하였다.
