Effects of growth temperature on structural and optical properties of ZnO thin films grown chemically on porous silicon substrate

Seed layer-free ZnO thin films were synthesised by chemical bath deposition method on porous silicon substrates. The effects of growth temperature on the structural and optical properties of ZnO thin films were systematically investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM) and photoluminescence (PL) spectroscopy. The grain size of the ZnO thin films gradually increases with increased growth temperature. The FESEM images displayed that the thickness of ZnO thin films increased with the increase in growth temperature. Meanwhile, photoluminescence measurements demonstrated a sharp and highly intense UV emission peak at growth temperature of 95 °C. This finding indicates that the optical and crystallographic properties of the ZnO thin films were improved with growth temperature of 95 °C.