Characterization of interfacial barrier charging as a resistive switching mechanism in Ag/Sb2Te3/Ag heterojunctions

Abstract

In this study, bipolar memristive behaviors were systematically characterized in Ag/Sb₂Te₃/Ag hetero-junctions. By using in situ Raman and photoluminescence spectroscopy, a direct observation of the bonding environment and band structure confirmed that resistive switches are strongly related to the electronic valence changes in Sb₂Te₃ and the formation of Schottky barriers at Ag/Sb₂Te₃ interfaces. Band movement of Sb₂Te₃ acquired by first-principles calculations also supports the electrostatic barrier charging as a memristive mechanism of Ag/Sb₂Te₃/Ag heterocells. Independent resistance-switching behaviors that can be utilized in both amorphous and crystalline Sb₂Te₃ lead to multiple resistance values with a large memory window (10⁴–10⁵) and low read voltage (∼0.2 V), giving rise to a unique multi-level memory concept. This study based on Ag/Sb₂Te₃/Ag hetero-junctions offers a significant understanding to promote the use of Sb₂Te₃ and other chalcogenide memristors as promising candidates for compatible high-density memory applications.