Tunable Negative Differential Resistance Effect in a-SZTO/Dielectric/SZTO Heterostructure TFTs at Room Temperature

We experimentally demonstrate the resonant tunneling and negative differential resistance (NDR) in a-SZTO/dielectric/SZTO heterostructure thin film transistors (TFTs) at room temperature (RT) for the first time. Here, we study the resonant tunneling and the NDR tunability for different middle-layer dielectric and gate biases. The dielectric materials of HfO 2, ZrO 2, and MgO are used in the a-SZTO/dielectric/SZTO heterostructure devices and are named SHS, SZS, and SMS in this work. The resonant tunneling through an insulator occurs when the energy bands of the two amorphous-SiZnSnO (a-SZTO) are aligned. The previous results of NDR based on resonant tunneling were obtained only using two-dimensional (2D) materials. But we observe the NDR results with a peak-to-valley current ratio (PVCR) of 3 at RT by utilizing the bulk (three-dimensional, 3D) oxide materials for the first time in this work.