Dipoles are formed at the MoS2/metal interfaces upon deposition of metals with a different work function on the MoS2 surface as a result of the charge redistribution. A Schottky barrier also forms, which hinders carrier injection from metal to MoS2 films. Experimental investigations on work function evolution of MoS2 under metal films and charge transfer at interfaces is critical in order to understand the interface mechanism and achieve a good ohmic contact.

Tuning the barrier height

The researchers use direct ultraviolet photoelectron spectroscopy to observe the different work functions of metals with different thicknesses, ranging from two dimensional to bulk, on MoS2 surface, as well as the interfacial charge transfer processes. The researchers find that the barrier height can be tuned by altering the deposited metal and its thickness. Moreover, a low work function metal is a good choice for the electrode in MoS2 electronic devices.

Tailoring the work function

The group find that the work function of molybdenum disulfide can be tailored by both the type and the thickness of the deposited metal (for example, Ni, Ti or Hf). It is hoped that further experiments will pave the way towards the future high performance MoS2 device applications.

More information about this research can be found in the journal Nanotechnology 27 344002.

Further reading

Bending behaviour of single layer molybdenum disulfide (May 2016)
Molybdenum disulfide nanosheets – Are they safe? (Jul 2015)
Titanium carbides: mechanical properties rival those of molybdenum disulphide (Jun 2015)