Enhanced Performance of MoS 2 Photodetectors by Inserting an ALD‐Processed TiO 2 Interlayer

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