Electrical switching of Si₂Te₃ thin films

As a silicon based 2D material, Si₂Te₃ has unique properties and potential applications in electronics. This work reports a bipolar resistive switching behavior observed in Si₂Te₃ thin film deposited on a Si substrate. The Si₂Te₃ thin films were grown at 850 ^oC by a CVD process. Transmission electron microscope (TEM), scanning electron microscope (SEM), Raman spectroscopy, X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDX) were used to study the crystal structure and properties of the as-grown Si₂Te₃ films, which confirm that the films have a hexagonal crystal structure and a Te to Si atomic percentage ratio of 1.6. The memory devices were fabricated by depositing silver thin films on top of Si₂Te₃ as an electrical contact. Under an applied voltage, the device switches from a high-resistance state (HRS) to a low-resistant state (LRS) and then switches back to HRS under a reversed voltage. The set voltage was found to be as low as 0.22 V, which provides an extremely small operation voltage for memory applications. The memory device is unstable under atmospheric conditions, which is expected due to the instability of Si₂Te₃ material in the air. However, the device was found to be stable in a vacuum.