Low-temperature hydrothermal growth of ZnO nanorods on sol-gel prepared ZnO seed layers: Optimal growth conditions

► Optimal synthesis conditions for well-aligned ZnO nanorods have been investigated. ► Sol-gel, spin-coating and hydrothermal methods have been applied. ► ZnO nanorods were synthesized in the range of 65-85 °C and 1-2 h growth time. ► The optimal conditions provide a way for obtaining a good quality of ZnO.