Nanostructured ZnO films prepared by hydro-thermal chemical deposition and microwave-activated reactive sputtering

•Nanostructured films of ZnO prepared by HCD and MARS methods•Nanostructures obtained by HCD are highly crystalline and grow as nanorods.•MARS films are dense and porous with cylindrical rods with hemi-spherical caps.

Nanostructured, highly porous, films of zinc oxide have been prepared by hydro-thermal chemical deposition and by microwave-activated reactive sputtering for applications in sensors and solar cells. Scanning electron microscopy, X-ray diffraction, optical constant measurements, and Raman spectroscopy are presented demonstrating the pronounced effect of microwave power on the nanostructure of films prepared by microwave-activated reactive sputtering and the marked differences between films grown by the two methods. While the structures obtained by hydro-thermal chemical deposition are highly crystalline and grow as nanorods, the microwave-activated reactive sputtering films are initially dense with subsequent increase in porosity, leading to unusual cylindrical structures with hemi-spherical caps.