Enhanced Performance of MoS Photodetectors by Inserting an ALD-Processed TiO Interlayer.

2D molybdenum disulfide (MoS ) possesses excellent optoelectronic properties that make it a promising candidate for use in high-performance photodetectors. Yet, to meet the growing demand for practical and reliable MoS photodetectors, the critical issue of defect introduction to the interface between the exfoliated MoS and the electrode metal during fabrication must be addressed, because defects deteriorate the device performance. To achieve this objective, the use of an atomic layer-deposited TiO interlayer (between exfoliated MoS and electrode) is reported in this work, for the first time, to enhance the performance of MoS photodetectors. The TiO interlayer is inserted through 20 atomic layer deposition cycles before depositing the electrode metal on MoS /SiO substrate, leading to significantly enhanced photoresponsivity and response speed. These results pave the way for practical applications and provide a novel direction for optimizing the interlayer material.