Flexible p-Type WSe Transistors with Alumina Top-Gate Dielectric.

Tungsten diselenide (WSe) field-effect transistors (FETs) are promising for emerging electronics because of their tunable polarity, enabling complementary transistor technology, and their suitability for flexible electronics through material transfer. In this work, we demonstrate flexible p-type WSe FETs with absolute drain currents || up to 7 μA/μm. We achieve this by fabricating flexible top-gated FETs with a combined WSe and metal contact transfer approach using WSe grown by metal-organic chemical vapor deposition on sapphire.

Imaging Spatial Distribution of Photogenerated Carriers in Monolayer MoS with Kelvin Probe Force Microscopy.

The spatial distribution of photogenerated carriers in atomically thin MoS flakes is investigated by measuring surface potential changes under light illumination using Kelvin probe force microscopy (KPFM). It is demonstrated that the vertical redistribution of photogenerated carriers, which is responsible for photocurrent generation in MoS photodetectors, can be imaged as surface potential changes with KPFM. The polarity of surface potential changes points to the trapping of photogenerated holes at the interface between MoS and the substrate as a major mechanism for the photoresponse in monolayer MoS.