High-Performance FETs with High-k STO by Optimized van der Waals Heterostructure Interface

The pursuit of suitable insulating layers and high-quality integration methods is important to further improve the performance of field-effect transistors (FETs). In this study, we employ transferable high- k oxide films as device gate dielectrics to fabricate high-quality optoelectronic devices by optimizing the interface between the dielectric material and the two-dimensional (2D) materials. Through meticulous refinement, a transferred film roughness of 269.27 pm was achieved, resulting in intact, crack-free SrTiO 3 films. The molybdenum disulfide (MoS 2 ) transistors exhibited remarkable characteristics, including a high on/off ratio ( I ON / I OFF ) of 1 × 10 8, a subthreshold swing as low as 69.2 mV/dec, and a field-effect mobility reaching 230 cm 2 /(V·s). Additionally, the SrTiO 3 films were combined with molybdenum telluride (MoTe 2 ) to fabricate PN junctions capable of functioning as photodetectors at extremely low operating voltages (±2 V). The exceptional performance of both the MoS 2 FETs and the MoTe 2 PN junctions can be attributed to the optimized, high-quality dielectric/semiconductor heterojunction interface. This further demonstrates the versatility of the van der Waals integration method employed in this research.