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

Abstract

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.

Keywords: atomic layer deposition; interlayer; molybdenum disulfide; photodetectors; titanium dioxide.