Synthesis, characterization and photoluminescence properties of ZnO hexagonal pyramids by the thermal evaporation method

ZnO hexagonal pyramids have been synthesized on silicon (1 0 0) substrates by thermal evaporation of metal Zn powder at a low temperature of 467 °C without a metal catalyst. Scanning electron microscopy and transmission microscopy observations show that the growth of hexagonal pyramids is initiated by the preferred nucleation ZnO grain or nanorod on Si substrate, followed by growth of hexagonal pyramids via vapor–solid growth process. The photoluminescence spectrum of the hexagonal pyramids shows two emission bands located at 380 and 503 nm. Because of their characteristic pyramid shape with a nanotip, hexagonal ZnO pyramids may be expected to be suitable for electronic and optoelectronic devices such as field emitters, atomic force microscopy probes, optoelectronic devices for medical diagnosis.