Nanowires piezoelectric constants determination using current-voltage measurements

This work demonstrates an original method using the electromechanical properties of the zinc oxide (ZnO) piezoelectric nanowires to characterize its piezoelectric voltage coefficient (d₃₃). The proposed technique utilizes the current-voltage (IV) measurements coupled with the application of variable force to cause a change in the corresponding IV relationship. To conduct the IV measurements, the nanowire is integrated inside a field effect transistor (FET) to form the channel of the device, while it is suspended over a trench. The indentation of the nano-wire causes the mechanical deflection of the suspended nanowire which through the piezoelectric effect changes the IV characteristics of the FET. The extraction of the piezoelectric coefficient is done by modifying the standard FET IV model to incorporate the change in the channel length which is triggered by the piezoelectric behavior. Embedded within this change of length is piezoelectric coefficient and therefore, it becomes straightforward procedure to extract this coefficient from the changes in the IV characteristics.