Large scale ultrathin opto-electronics using 2D materials grown by chemical vapour deposition

2D monolayers of transition metal dichalcogenides (TMDs), such as MoS2 and WS2, are direct band gap semiconductors and offer new approaches to creating ultrathin, transparent and flexible electronics by integrating with graphene. Graphene's semi-metal band structure gives rise to new behavior as an electrode in contact with the 2D TMDs that modulate the transistor and photodetector behavior. In this talk I will discuss our latest results on how to create arrays of all 2D devices using only CVD grown 2D materials, in both lateral geometry and vertical stacked configurations. I will show how simple layer by layer assembly can create large scale arrays of cross bar graphene electrodes with MoS2 or WS2 in between and the unique photoresponse these systems have. I will then compare the photo-physics to those in lateral form and explain the mechanisms of charge transfer and doping. The layer dependent response of devices will be reported along with the enhancement of photodetectors by using MoS2/WS2 stacks with type II band offset.