Electrochemical growth and control of ZnO dendritic structures

The dendritic crystal growth patterns that typically grow along principal crystallographic axes and have the hierarchical structure have been attracting much attention from scientists for several centuries. Here we report that the ZnO dendritic nanostructure as a new member of the ZnO family could be successfully prepared on Cu substrates by electrochemical deposition in the solution of ZnCl2 + citric acid at a temperature of 90 degrees C. Furthermore, our synthetic parameters allow further structural manipulation. The morphology evolvement from dendritic structures to nanorods could be successfully realized when KCl as supporting electrolyte was added to the deposition solution. The green light emission band of the ZnO dendritic structure prepared in 0.05 M ZnCl2 + 0.05 M citric acid is almost negligible, indicating that these ZnO deposits are highly crystallized and of excellent optical quality. The PL spectra of the as-grown ZnO nanorods show they possess many oxygen vacancies, and the acquired ZnO nanorods have a potential application in sensors.