Nanostructure Vanadium-doped Zinc Oxide Film Sensor Endowed with Enhanced Piezoelectric Response **Resrach supported by the National Natural Science Foundation of China (Grant No. 51775446).

We present a performance-enhanced piezoelectric sensor utilizing nanostructure Vanadium-doped zinc oxide (ZnO) thin film aiming at sensitively measuring underwater sound signals. The sensor is fabricated by MEMS technology using a 6-mask ZnO-on-SOI process platform. Individual sensor with a low foot-print of 2 mmx2mm could be easily assembled working as a hydrophone. Sensing element based on the V-doped ZnO film is endowed improved piezoelectricity with the piezoelectric constant of 110.3 pm/V. Demonstrations in a plane-wave tube test system confirm that the output voltage of the V-doped ZnO film sensor obviously increases by an order of magnitude compared with the pure ZnO film sensor with same dimensions, showing great potential in the field of underwater acoustic detection.