High-quality vertically aligned zinc oxide nanorods were successfully grown on p-type 6H–SiC substrate by microwave-assisted chemical bath deposition. The novel seed material poly(vinyl alcohol)–Zn(OH)2 nanocomposites was used to seed the 6H–SiC substrate. X-ray diffraction analysis and field emission scanning electron microscopy showed that the synthesized ZnO nanorods were vertically well aligned in the direction of the (002) plane of the hexagonal structure. The optical properties were examined by photoluminescence spectroscopy, which showed a high-intensity UV peak compared with visible defect peaks. The current–voltage property proved the good rectifier characteristic of the n-type ZnO nanorod/p-type SiC diode heterojunction. The electroluminescence emission of the heterojunction LED was sufficiently high to be seen with the naked eye, with a broad peak centered at the green part of the visible spectrum.