Improvement of LiNbO 3 thin film quality via pulsed laser deposition with Li-rich targets for memristor applications

Ferroelectric tunnel junctions have attracted widespread attention due to their nonvolatile resistive state storage capability and great potential for emulating artificial synaptic structures. LiNbO 3 , as a ferroelectric material with strong spontaneous polarization, is often used in ferroelectric tunnel junctions. However, LiNbO 3 thin films grown epitaxially by pulsed laser deposition typically suffer from low quality, leading to issues such as low ON/OFF ratio and unstable device performance. In this work, epitaxial thin films were grown using a Li 1.1 NbO 3 target with a Li/Nb ratio of 1.1. The improvement in film quality was confirmed in terms of oxygen vacancy concentration and polarization switching performance. Li 1.1 NbO 3 -based and LiNbO 3 -based ferroelectric tunnel junctions were fabricated and compared. It was found that the Li 1.1 NbO 3 -based devices exhibit enhanced electrical performance, and the electrical transport mechanism is analyzed. In addition, the Li 1.1 NbO 3 -based devices simulate superior artificial synaptic plasticity, demonstrating their promising application prospects.