Polarization of Bi_2Te_3 thin film in a floating-gate capacitor structure

摘要

Metal-Oxide-Semiconductor (MOS) capacitors with Bi_2Te_3 thin film sandwiched and embedded inside the oxide layer have been fabricated and studied. The capacitors exhibit ferroelectric-like hysteresis which is a result of the robust, reversible polarization of the Bi_2Te_3 thin film while the gate voltage sweeps. The temperature-dependent capacitance measurement indicates that the activation energy is about 0.33 eV for separating the electron and hole pairs in the bulk of Bi_2Te_3, and driving them to either the top or bottom surface of the thin film. Because of the fast polarization speed, potentially excellent endurance, and the complementary metal-oxide-semiconductor compatibility, the Bi_2Te_3 embedded MOS structures are very interesting for memory application.