Role of semiconductor layer thickness in the electrical properties of BaTiO₃-based MFIS-heterostructured devices

Thin-film-based layered Metal-Ferroelectric-Insulator-Semiconductor (MFIS) heterostructure devices have been investigated using the Ag (metal)/BaTiO₃ (Ferroelectric)/SrTiO₃ (Insulator)/ZnO (Semiconductor) multilayer structure fabricated on the SrTiO₃ (100) single crystalline substrate. MFIS-structured devices were prepared using the Pulsed Laser Deposition (PLD) technique by varying the thicknesses of the semiconductor channel (ZnO). X-ray diffraction measurements (XRD) show the (100)-oriented growth of BaTiO₃ layer whereas (0002) and (11–20)-oriented growth of ZnO layers. Microstructure measurements carried out using Atomic Force Microscopy (AFM) on BaTiO₃ and ZnO surfaces showing the homogenous granular structure. To understand the Charge conduction mechanism, cyclic I-V measurement has been carried out and understands the responsible mechanism with and without UV illumination. In addition, role of semiconductor channel thickness on the channel resistance and resistive switching has been investigated and verified with charge conduction mechanism. It is observed that Fowler—Northeim tunneling and space-charge limit conduction mechanism explain the I-V behavior and resistive switching collectively.