Large-scale flexible and transparent electronics based on monolayer molybdenum disulfide field-effect transistors

Atomically thin molybdenum disulfide (MoS2) is a promising semiconductor material for integrated flexible electronics due to its excellent mechanical, optical and electronic properties. However, the fabrication of large-scale MoS2-based flexible integrated circuits with high device density and performance remains a challenge. Here, we report the fabrication of transparent MoS2-based transistors and logic circuits on flexible substrates using four-inch wafer-scale MoS2 monolayers. Our approach uses a modified chemical vapour deposition process to grow wafer-scale monolayers with large grain sizes and gold/titanium/gold electrodes to create a contact resistance as low as 2.9 k Omega mu m(-1). The field-effect transistors are fabricated with a high device density (1,518 transistors per cm(2)) and yield (97%), and exhibit high on/off ratios (10(10)), current densities (similar to 35 mu A mu m(-1)), mobilities (similar to 55 cm(2) V-1 s(-1)) and flexibility. We also use the approach to create various flexible integrated logic circuits: inverters, NOR gates, NAND gates, AND gates, static random access memories and five-stage ring oscillators.