The Effects of Mechanical Thin-film Properties on the Pyroelectric Signals

The ZnO pyroelectric sensors with configuration of partially covered electrode were used to discuss the correlation between its voltage responsivity, morphology and mechanical properties of the thin film. The sensor based on pyroelectric thin film deposited by sputtering with RF power of 120 W was revealed higher voltage responsivity than those of 150 W and 90 W for 10-400 times. Meanwhile, the surface morphology reveals less defects and uniform grain size for the RF power of 120 W as characterized by SEM, which can be a symptom of the high voltage responsivity. On the other hand, the effective elastic modulus and hardness of ZnO film sputtered with RF power of 120 W were significantly (P Lt 0.05) larger than that of 90 W (21%) and (32%), and 150 W about 23% and 37%, respectively. Therefore, the effects of sputtering power on the voltage responsivity of the pyroelectric sensor can be analyzed and interpreted by the SEM morphology and its mechanical properties.