Ohmic Contact Engineering for MoS₂ Neuromorphic Performance Enhancement

Two-dimensional transition metal dichalcogenides (2D TMDs) have sparked a lot of interest for neuromorphic device fabrication due to their phase-tuning properties at the atomic level. To overcome the limitations of traditional memory devices, numerous research approaches have been investigated using 2D materials including phase transition, filament formation, and ion/vacancy migration. However, challenges such as reliability, phase stability, and power consumption still exist because of having fermi level pinning effect of metal semiconductor contact, which is attributed to orbital overlap and defects. It is essential to investigate how to lower contact resistance to develop efficient semiconducting devices. This is the first time we've employed semi-metal electrodes in a 2D MoS₂ FET (field effect transistor) to develop efficient neuromorphic memory devices by minimizing contact resistance. We observed several positive neuromorphic behaviors such as I-V hysteresis, potentiation, depression, and highly efficient spike rate dependent plasticity (SRDP) by reducing contact resistance utilizing semimetal Bi on 2d layered MoS₂ compared to other metal electrodes such as Ti, Cu, and Au. We are still exploring shottkey barrier height modulation caused by various metals and semimetals, as well as its interfacial properties, to realize the reduction of contact resistance effect on neuromorphic device performance.