Response and recovery times are defined as the time when 90% of the full signal change induced by hydrogen absorption/desorption is achieved. The signal change of the annealed film rises by approximately 50% over the Fig film before annealing. Attributed to the grain growth and stress relaxation, it obviously shows that the drift of baseline is reduced from 7 mV to 1 mV, in other words, the proportion of zero drift in response value decreases from 24.7% to 2.4%.