Morphological variations and structural properties of ZnO nanostructures grown by rapid thermal CVD

Various nanostructures of ZnO such as nanowires, sea urchin like and nano needles were grown using rapid thermal chemical vapor deposition technique (RTCVD), in oxygen ambient. For the growth of such structures, oxygen pressure was kept as 0.1 Torr whereas the chamber base pressure was 10(-5) Torr. The growth temperature was varied from 600 degrees C to 850 degrees C, which resulted in morphological variations. X-ray diffraction measurement revealed the hexagonal wurtzite structure of ZnO preferably oriented in [001] direction, which was further confirmed by high-resolution transmission electron microscopic (HRTEM) observations. X-ray photoelectron spectroscopy (XPS) analysis suggests the presence of Zn 2p and O 1s. Raman E2 high peaks at approximately 434 cm(-1) has the highest intensity compared to other modes supports XRD results. Presence of low E2 peaks at approximately 330 cm(-1) indicates defects and oxygen vacancies.