|About this Abstract
||2010 Electronic Materials Conference
||TMS 2010 Electronic Materials Conference
||AA7, Low Temperature Electrochemical Growth of ZnO Nanobelts, Nanowalls, Nanospikes and Nanowires: Growth Mechanism and Field Emission Study
||Debabrata Pradhan, Kam Tong Leung
|On-Site Speaker (Planned)
ZnO nanostructures are promising materials with a potential for several applications such as in the photonics, opto-electronics, electron field emissions and solar cells. In the present work, we deposited both the two-dimensional (i.e. nanowalls and nanobelts) and one-dimensional (i.e. nanospikes and nanowires) ZnO nanostructures on inexpensive conducting glass and plastic substrate using a facile electrochemical deposition technique. All the electrodeposition experiments were performed below 70°C. The electrolyte concentration, deposition temperature and deposition potential were found to significantly control the morphology of ZnO nanostructures. Glancing angle X-ray diffraction and transmission electron microscopy were used to obtain the crystallinity and growth direction of different ZnO nanostructures. Energy dispersive X-ray analysis and depth profiling X-ray photoelectron spectroscopy were used to measure the composition of as-synthesized materials, which suggested the cause for different nanostructure formation. In particular, Cl<SUP>-</SUP> ions capping on the preferred  growth direction of ZnO under fast hydroxylation kinetics condition observed at a higher Zn(NO<SUB>3</SUB>)<SUB>2</SUB>.6H<SUB>2</SUB>O electrolyte concentration (>0.05 M). The electron field emission measurement showed higher emission current density at a lower electric field from the nanospikes as compared to that of the nanowalls. This is attributed to the tapered tips of the nanospikes geometry which concentrates a higher electric field in comparison to the nanometer thick ledge of nanowalls. The nanospikes showed a turn-on electric field of 3.2 V/μm for 1 μA/cm<SUP>2</SUP> and threshold field of 6.6 V/μm for 1.0 mA/cm<SUP>2</SUP>. This superior field emission property makes the nanospikes to be one of the best ZnO field emitter fabricated on a glass substrate at low temperature.