Ferroelectrics are crucial components for a wide spectrum of applications, including nonvolatile memories[1,2,3]. In order to avoid the destructive readout of data, process that usually takes place in capacitor geometries, ferroelectric field-effect transistor devices (FeFET) are preferred nowadays. Alongside the memory function, FeFET come with the logical functions of transistors (switching and amplifying). The combination of PZT (ferroelectric) and a-IGZO (channel semiconductor) has great potential for processing FeFET with good memory response. Furthermore, both materials are transparent in the visible spectrum. In this study, the memory function of PbZr0.2Ti0.8O3 integrated in metal-ferroelectricsemiconductor (MFS) and FeFET architectures has been investigated. It was found that the key parameter that influence the memory performance of the studied structures is the temperature, which controls the capacitance-voltage hysteresis direction through the a-IGZO-PZT interface defect states. The structural and optical properties of the heterostructures were also considered. The fully transparency of the fabricated devices was assured by using F:SnO2 (bottom/gate electrode) coated glass substrate. The PZT layer was prepared by sol-gel technique, a-IGZO and top (source and drain) electrodes were deposited by magnetron sputtering.