Labyrinth patterns of zinc oxide on porous silicon substrate

•Formation of substrate treatment dependent zinc oxide micro-morphologies.•Formation of granular Labyrinth patterns with high surface to volume ratio over the un-oxidized substrate.•Low porosity oxidized substrate resulted in a relatively flat granular structure.

The substrate treatment dependent formation of different micro-morphologies of zinc oxide over PS substrate has been reported. Effect of substrate oxidation and annealing has been studied. Changes in the structural properties were seen in the form of labyrinth patterns developed on the surface and were studied with the help of scanning electron microscope (SEM), atomic force microscope (AFM). X-ray diffraction (XRD) along with UV–visible absorption and photoluminescence (PL) spectroscopy were performed for characterizing the zinc oxide film and the hybrid structure. A relatively flat film of nanostructured zinc oxide particles is found to form on the oxidized substrate as compared to the nanostructured labyrinth patterns formed on the un-oxidized substrate with enhanced aspect ratio. Such micromorphologies can be very promising for fabricating highly sensitive gas sensors.