Impedance analysis of CuBr films for ammonia gas detection

CuBr films prepared by magnetron sputtering can be used to design a selective and sensitive ammonia microsensor, operating at ambient temperature. Impedance spectra of the films under different gas atmospheres can be fitted by a simple equivalent circuit. The roughness of the electrode/solid electrolyte interface leads to a distribution of the electrode resistance and capacitance values. The evolution of the bulk resistance of CuBr can be attributed to sorption of ammonia molecules, which is also investigated by Fourier-transform infrared (FTIR) spectroscopy.