Properties of single-phase gallium nitride (GaN) films formed using a Ga(S2CN(CH3)2)3 nanoparticle solution

Ga(S2CN(CH3)2)3 (Ga(DmDTC)3) nanoparticles (diameter: ∼28.5 nm) were synthesized using an ultrasonic spray method, and Ga(DmDTC)3 films were deposited using a spin coating technique. The GaN films were formed by the pyrolytic transformation of Ga(DmDTC)3 films under a NH3 atmosphere at 850 °C for 10 min. The as-formed GaN films exhibited a hexagonal Wurtzite structure with a (0002) preferred orientation and showed strong photoluminescence centered at 2.95 eV. The Ga to N elemental ratio was 1:0.9 with sulfur detected in small amounts in the XPS spectrum. This result showed that almost all of the sulfur atoms in the Ga2S3 were replaced with nitrogen atoms, and the remaining sulfur atoms formed sulfur-doped GaN (GaN:S) under the NH3 environment. Furthermore, epitaxial GaN films on the pyrolytic GaN films, which were formed by MOCVD, exhibited lateral growth, whereas the GaN films on bare sapphire substrates were grown upward toward the z-axial direction. The developed method in this study is a simple technique to form single-phase GaN films using a liquid precursor and can be useful as a semi-homo substrate for GaN epitaxial growth.