Poly- and single-crystalline h-GaN grown on SiCN/Si(100) and SiCN/Si(111) substrates by MOCVD

This paper reports the growth of polycrystalline GaN on Si(100) and single-crystalline h-GaN on Si(111) substrates with a single-crystalline SiCN burffer layer by metalorganic chemical vapor deposition (MOCVD). From high-resolution x-ray diffraction (HRXRD) and scanning election microscopy (SEM) analyses, GaN on SiCN/Si(100) is polycrystalline and GaN on SiCN/Si(111) is single-crystalline. From photoluminescence analysis, the energy gaps of h-GaN/SiCN/Si(100) and c-GaN/SiCN/Si(100) are ∼3.4 and ∼3.2 eV at 300 K but shift to 3.5 and 3.3 eV at 15 K, respectively. A model to explain the growth mechanism is also proposed.