A high-sensitivity room-temperature hydrogen gas sensor based on oblique and vertical ZnO nanorod arrays

► We synthesized high quality vertically and oblique aligned ZnO nanorods on sapphire substrate. ► We used PVA-Zn(OH)2 nanocomposites as a novel seed materials for microwave assisted-CBD. ► High sensitivity of 500% to H2 was examined at RT for ZnO nanorod arrays. ► The oblique/vertical nanorods were the key factors for the high sensitivity.