In Situ Modulation of the Au-MoS2 Contact Barrier via Triboelectric Plasma-Assisted Electron Injection

Abstract Two-dimensional (2D) van der Waals materials, especially transition-metal dichalcogenide molybdenum disulfide (MoS2), have emerged as key candidate materials for advancing optoelectronics and integrated circuits due to their unique physical properties. However, the high contact barrier between the metal and semiconductor has hindered further performance improvement. Here, we introduce a novel triboelectric plasma regulation technique aimed at reducing the contact barrier between the metal and semiconductor. By injecting electrons into the S-vacancy and keeping them at the defect sites, stable electron-vacancy complexes are formed, which induce an external reverse electric field and effectively reduce the contact potential barrier between the metal and the semiconductor. At the same time, the efficiency of free-carrier injection is enhanced, significantly improving the optoelectronic performance and gate modulation capability of the device. The results show that the photoresponse performance and gate modulation ability of MoS2 devices grown by chemical vapor deposition (CVD) have been improved by 22 times and 3 orders of magnitude, respectively. This triboelectric plasma regulation technique demonstrates great potential for optimizing the performance of 2D semiconductor devices.