Enhanced Performance of MoS₂ Photodetectors by Inserting an ALD-Processed TiO₂ Interlayer

2D molybdenum disulfide (MoS₂) 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 MoS₂ photodetectors, the critical issue of defect introduction to the interface between the exfoliated MoS₂ 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 TiO₂ interlayer (between exfoliated MoS₂ and electrode) is reported in this work, for the first time, to enhance the performance of MoS₂ photodetectors. The TiO₂ interlayer is inserted through 20 atomic layer deposition cycles before depositing the electrode metal on MoS₂/SiO₂ 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.