Ultraviolet-emitting javelin-like ZnO nanorods by thermal evaporation: Growth mechanism, structural and optical properties

Ultraviolet-emitting, single-crystalline aligned javelin-like zinc oxide (ZnO) nanorods were synthesized on copper foil by thermal evaporation at low temperature of 500 °C without catalysts or additives. Detailed structural characterizations confirmed that the formed products are single-crystalline, they possess a wurtzite hexagonal phase and are grown along the c-axis direction. Raman-active optical-phonon E2 mode at 437 cm−1 with sharp and strong UV emission at 381 nm in room-temperature photoluminescence spectrum showed that the obtained ZnO nanorods have a good crystal quality with excellent optical properties. Moreover, a detailed growth mechanism was proposed for the formation of the javelin-like ZnO nanorods.