Polarization-Enabled Piezoelectric Tellurium–Selenium (Te_xSe_1–x) Thin Films for Memory Switching and Artificial Synaptic Functions

Two-dimensional materials with piezoelectricity and polarization-enabled electromechanical responses provide a promising basis for multifunctional electronics, including memory devices and neuromorphic computing. In this work, we explore cryogenic physical vapor deposition (cryogenic PVD)–grown Te_xSe_1-x thin films, a tellurium-based compound with a tunable bandgap and enhanced non-centrosymmetry, and examine their polarization-associated electromechanical characteristics. A 10 nm Te_0.9Se_0.1 film exhibits a clear switchable electromechanical response with a piezoelectric coefficient d₃₃ of 33 pm/V, together with stable piezoresponse under ambient conditions. Introducing a Se ratio of 0.1 is found to enhance the polarization behavior and domain response while maintaining the crystalline quality of the Te_xSe_1-x films. Memory devices based on Te_0.9Se_0.1 show retention beyond 2000 s and remain switchable up to 1000 cycles, with an HRS/LRS ratio exceeding 10² under ± 20 V program/erase pulses when read at a drain voltage of 1 V. In addition, synaptic behavior is demonstrated with 92% image recognition accuracy at low energy consumption, suggesting potential for neuromorphic applications. These results highlight the potential of Te_xSe_1-x films as a polarization-enabled piezoelectric semiconductor system for future low-power memory and computing applications.