Fall 2012 IAB & Research Review
September 19 to 21
Monolayer Semiconductor Devices
Monolayer chalcogenides have recently been shown promising for future scaled electronics. We report high performance p-type field-effect transistors based on single layered (thickness, ~0.7 nm) WSe2 as the active channel with chemically doped source/drain contacts and high-ê gate dielectrics. The top-gated monolayer transistors exhibit a high effective hole mobility of ~250 cm^2/Vs, perfect subthreshold swing of ~60 mV/dec, and ION/IOFF of >10^6 at room temperature. Special attention is given to lowering the contact resistance for hole injection by using high work function Pd contacts along with degenerate surface doping of the contacts by patterned NO2 chemisorption on WSe2. The results here present a promising material system and device architecture for p-type monolayer transistors with excellent characteristics. Applications of monolayer semiconductor devices for various types of sensors will also be explored.