Sensitivity of ZnO films doped with Er, Ta and Co to NH₃at room temperature

The sensitivity of ZnO films, undoped and doped with Er, Ta and Co, to exposure to NH3 has been studied. The films were deposited by magnetron co-sputtering of a sintered ZnO target with chips of the different doping elements on its surface. The sensitivities of the ZnO films to exposure to NH3 were measured by the quartz crystal microbalance method using the resonance frequency shift. The adsorption process was investigated over an aqueous solution of ammonia with 100 ppm concentration. The speed and the mass of sorption were calculated on the basis of the time-frequency characteristic. (c) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.