Investigation of the ferroelectric properties and dynamics of nanodomains in LiNbO3 thin films grown on Si (100) substrate by scanning probe microscopy techniques

In this work, scanning probe microscopy (SPM) in the so-called piezoresponse mode (PFM) is used to image the morphology, as-growth domain structure, domain wall motion and piezoelectric loop in lithium niobate thin films. A RF magnetron sputter system was used to deposit LiNbO3 thin films on (100)-oriented Si substrates with SiO2 layer. The surface of the sample shows small grains which diameter ranges from 30 nm to 50 nm and roughness is less than 8 nm. Ferroelectric nanodomains were created in LiNbO3 thin films by applying a voltage to a sharp conducting tip of a PFM. Using the piezoresponse mode of the SPM to detect the out-of-plane and in-plane film polarization, the domain sizes were measured as a function of the applied writing voltage and the pulse time. The dynamics of domain growth is analyzed experimentally taking into account the strong inhomogeneity of the external electric field in the film and the influence of the Si substrate.