Large-Scale Flexible Electronics on Ultrathin Glass Using Low-Temperature Grown MoS2

The synthesis of high-quality MoS₂ in a large area plays a crucial role in realizing industrial applications of nanoelectronics, flexible devices, and optoelectronics. However, the current wafer-scale MoS₂ using chemical vapor deposition (CVD) process requires a high growth temperature, which limits its application in device fabrications.¹ As indicated by the Mo-S binary phase diagram, semiconducting MoS₂ is considered as a width compound, in which the defects are drastically increased by reducing the growth temperature.² The lowest reported temperature at which MoS₂ still exhibits semiconductor properties is 320 °C.³ Subsequently, a transfer step is required to bring MoS₂ from as-grown substrate to a targeted substrate, especially for the realization of flexible electronics that requires a flexible substrate such as polymer or ultrathin glass. It raises the issue of quality degradation due to residues and wrinkles caused by the transfer step. By lowering the growth temperature, MoS₂ can be deposited on ultrathin glass, which can be used straightly for flexible electronics. Also, the quality of MoS₂ can be preserved by the direct fabrication without the transfer step. Herein, the development of a new method to synthesize high-quality MoS₂ using a metal-organic CVD (MOCVD) system at low temperature (i.e ~150 °C) is proposed, and low temperature grown MoS₂ is applied to electronic applications such as photodetector and logic circuits. This method offers not only cost-effective but can be used for low melting temperature substrates such as polymers.<br/>References<br/>[1] Li, Taotao, et al.: Epitaxial growth of wafer-scale molybdenum disulfide semiconductor single crystals on sapphire. Nature Nanotechnology, 2021.<br/>[2] Hoang, Anh Tuan, et al.: Epitaxial growth of wafer-scale molybdenum disulfide/graphene heterostructures by metal–organic vapor-phase epitaxy and their application in photodetectors. ACS Applied Materials & Interfaces 12, pp. 44335-44344, 2020.<br/>[3] Park, Ji-Hoon, et al.: Synthesis of high-performance monolayer molybdenum disulfide at low temperature. Small 5, 2000720, 2021.