Low-Temperature Synthesis of Transfer-Free Molybdenum Disulfide Films for Two-Dimensional Memristors

Two-dimensional (2D) materials are promising for resistive random-access memory (RRAM) applications due to their notable scalability and switching characteristics. RRAM devices using 2D monolayers experience the shorting issue that reduces device yield. However, synthesizing multilayer 2D materials, for instance, via chemical vapor deposition, is often complicated by the thermodynamic limitations inherent in layer-by-layer epitaxial growth. This letter reports a low-temperature (400°C) synthesis of multilayer molybdenum disulfide (MoS<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub>) films via thermal decomposition of spin-coated ammonium tetrathiomolybdate. This method produces uniform MoS2 films with controlled thickness (1.5-5 nm) directly on substrates containing pre-patterned bottom electrodes. The fabricated RRAM devices exhibit nonvolatile switching with SET/RESET voltages of 1.2 V and -0.6 V, respectively, a resistance ratio of 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>, and endurance over 10<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> cycles. DC sweep measurements suggest that SET operation follows trap-controlled space-charge-limited conduction. The transfer-free synthesis method satisfies back-end-of-line (BEOL) thermal constraints and enables scalable integration of 2D materials in memory applications.