Fabrication and characterization of ZnO single nanowire-based hydrogen sensor

Vertically aligned ZnO nanowires were grown on c-plane sapphire substrate by metal organic chemical vapor deposition technique. The nanowires were single crystalline and structurally uniform and did not exhibit any noticeable defects. Pt/ZnO single nanowire Schottky diodes were fabricated by using e-beam lithography and then characterized by measuring temperature-dependent I-V characteristics. The diode exhibited a low Schottky barrier height of 0.42 V and ideality factor of 1.6 at room temperature. Temperature-dependent hydrogensensing measurements were carried out with different hydrogen concentrations. A good sensing characteristic (S ≈ 90%) has been observed at room temperature with a response time of ∼55 s.