Monolayer MoS 2 field-effect transistors patterned by photolithography for active matrix pixels in organic light-emitting diodes

Two-dimensional molybdenum disulfide (MoS 2 ) has substantial potential as a semiconducting material for devices. However, it is commonly prepared by mechanical exfoliation, which limits flake size to only a few micrometers, which is not sufficient for processes such as photolithography and circuit patterning. Chemical vapor deposition (CVD) has thus become a mainstream fabrication technique to achieve large-area MoS 2 . However, reports of conventional photolithographic patterning of large-area 2D MoS 2 -based devices with high mobilities and low switching voltages are rare. Here we fabricate CVD-grown large-area MoS 2 field-effect transistors (FETs) by photolithography and demonstrate their potential as switching and driving FETs for pixels in analog organic light-emitting diode (OLED) displays. We spin-coat an ultrathin hydrophobic polystyrene layer on an Al 2 O 3 dielectric, so that the uniformity of threshold voltage ( V th ) of the FETs might be improved. Our MoS 2 FETs show a high linear mobility of approximately 10 cm 2 V −1 s −1 , due to a large grain size around 60 μm, and a high ON/OFF current ratio of 10 8 . Dynamic switching of blue and green OLED pixels is shown at ~5 V, demonstrating their application potential.