  Two-probe electronic transport measurements on a Molybdenum Disulphide
(MoS_2) surface were performed at low temperature (30K) under ultra-high vacuum
conditions. Two scanning tunneling microscope tips were precisely positioned in
tunneling contact to measure the surface current-voltage characteristics. The
separation between the tips is controllably varied and measured using a high
resolution scanning electron microscope. The MoS_2 surface shows a surface
electronic gap (E_S) of 1.4eV measured at a probe separation of 50nm.
Furthermore, the two- probe resistance measured outside the electronic gap
shows 2D-like behavior with the two-probe separation.
