Morphological, structural and photoresponse characterization of ZnO nanostructure films deposited on plasma etched silicon substrates

ZnO nanostructure films were deposited by radio frequency (RF) magnetron sputtering on etched silicon (100) substrates using dry Ar/SF6 plasma, at two etching times of 5 min and 30 min, and on non etched silicon surface. Energy dispersive X-ray (EDX) technique was employed to investigate the elements contents for etched substrates as well as ZnO films, where it is found to be stoichiometric. Surface and growth evolution of films were explored by scanning electron microscope (SEM) images and found to have morphological development from spherical forms into nanowires with increasing substrate etching time. 2D atomic force microscope (AFM) images clarify this modification of the morphology and roughness values are deduced. Structural study was investigated using X-ray diffraction (XRD) patterns. The films had (002) preferential orientation with various etching time substrates. Optical characterization illustrated a decrease of reflectance with the morphological modification. Photoresponse measurement has been investigated and correlated with the crystallinity.