Structural, Optical, and Electrical Properties of Sputtered ZnO Thin Films and Their Application in Transparent Memory Devices

We report on the fabrication of ZnO thin films using a lab-made DC sputtering process. The ZnO films were prepared at several applied sputter voltages at fixed deposition times. The properties of the deposited films were characterized by x-ray diffraction, x-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and UV–visible spectroscopy. The ZnO thin films exhibited a polycrystalline phase in the dominant (100) plane, with film thicknesses in the order of approximately 50–80 nm. In addition, a transparent memory device based on the ZnO film was successfully fabricated with a device structure of ITO/ZnO/EVA/ITO. The fabricated device exhibited high optical transparency of approximately 70% in the visible light region. The fabricated memory device demonstrated memory properties with a maximum ON/OFF current ratio of 4.66 × 103 and showed good retention properties.