Formation of Nanorods of Undoped and Doped ZnO

Nanocrystalline zinc oxide has unique properties and immense application potential toward nanodevice fabrication. Moreover, piezoelectric properties of nanostructural materials can be tuned to meet specific application needs. Nanocrystalline ZnO as well as Cu-doped ZnO was synthesized in our laboratory. Synthesis of samples with dopant concentrations ranging from 1 to 10 atomic% was carried out. Post-synthesis calcinations of these ceramic oxides at 100 °C and 300 °C resulted in formation of nanocrystalline powders with narrow size distribution. Crystallite size increased from 10 to 70 nm when calcination temperature rose from 100 °C to 700 °C for undoped ZnO. Nanorods of ZnO could be clearly seen in SEM and AFM images. Dimensions were found to be 10 nm diameter and 100 nm length at temperature below 300 °C. SEM results revealed that in the case of doped ZnO, the crystallite size varied with increase in dopant concentration. After ascertaining crystallographic phase purity and completing necessary characterization by powder XRD, SEM, and AFM, piezoelectric response of these samples in pellet form was studied at nanometric scale using scanning probe microscopy. In this paper, this enhanced piezoresponse is being correlated with microstructural features.