Giant tunneling electroresistance in ferroelectric tunnel junctions using freestanding PbTiO₃ membranes

Ferroelectric tunnel junction (FTJ) is considered one of the promising emerging non-volatile memories. In recent years, the development of freestanding ferroelectric has provided greater freedom for the preparation and performance control of FTJs. In this work, we prepared a series of PbTiO 3 freestanding ferroelectrics with different thicknesses and successfully transferred them to Nb:SrTiO 3 or Si substrates to prepare tunnel junction devices. The structure of the freestanding ferroelectrics was characterized by X-ray diffraction and transmission electron microscopy, confirming the high quality of the ferroelectric before and after the transfer and the existence of structural distortion. Based on piezoelectric force response microscopy and macroscopic electrical measurements, the domain switching and electrical properties of the FTJ were carefully characterized. The ON/OFF ratio of the prepared freestanding FTJ was as high as 10 8 , and it is expected to reach 10 6 after 10 years of retention. The mechanism behind performance differences between the freestanding FTJ and the traditional tunnel junction is analyzed. In addition, we also studied the effect of light illuminance on the performance of the freestanding FTJ.