Detection of hydrogen with SnO2-coated ZnO nanorods

Abstract SnO 2 -coated ZnO nanorods on c -plane sapphire substrates were synthesized by pulsed laser deposition. The thickness of the polycrystalline SnO 2 was ∼10 nm, as determined by high-resolution transmission electron microscopy, while the diameter of the ZnO nanorods was ∼30 nm. The sensitivity of the SnO 2 /ZnO structures to hydrogen was tested by depositing Ti/Au Ohmic contacts on a random array of the nanorods and measuring the current at fixed voltage. There was no response to 500 ppm H 2 in N 2 at room temperature, but we obtained a sensitivity of ∼70% at 400 °C. The SnO 2 /ZnO structures exhibit drift in their recovery characteristics and for sequential detection of hydrogen, as generally reported for SnO 2 thin film sensors.