Achieving Quasi Intrinsic MoS₂ Performance via Liquid-Based Neutralization of Material and Interface Defects with H⁺ Protons

Semiconductor fabrication introduces imperfections such as dangling bonds and charge traps on channel surfaces and interfaces. Addressing these defects becomes challenging with miniaturized structures and low-dimensional materials, because high-energy treatments may cause secondary damage. Ionized hydrogen in the liquid phase neutralizes negatively charged defects through chemical reactions. The bis(trifluoromethanesulfonyl)imide (H-TFSI) solution, effective in mitigating defects in MoS₂, lacks verification of its mechanism and impact on device performance. Treating monolayer MoS₂ FET with H-TFSI induces simultaneous enhancement and degradation, complicating our understanding of the specific reactions. This study employed monolayer and multilayer MoS₂ devices to distinguish the surface and gate dielectric interface influence. In addition to the DC measurements for device performance analysis, low-frequency noise characteristics were examined to provide a more detailed depiction of the interface traps. Treating multilayer MoS₂ with H-TFSI results in more than a 2-fold increase in carrier mobility, and applying a negative gate voltage to further enhance the hydrogen ion reaction leads to a mobility increase exceeding 3-fold, reaching a high value of 128.3 cm²/V s compared to the baseline device. The interface trap density decreased, and the threshold voltage shifted positively. This signifies that the hydrogen ions from H-TFSI validated their remarkable healing effects on the surface and interface defects in MoS₂ devices by demonstrating their superior performance in passivating interface traps and neutralizing material defects.