Fig. 4: Layer dependent physical properties of MoS₂.

a Local variation of the work function as recorded in KPFM. (Scan rate: 20 µm/s) and b SECM feedback for a bilayer within a monolayer MoS₂ flake. (Scan rate: 20 µm/s, V_{WE-RE (Ag)}: 0.2 V, DmFc mediator). c Band gap and conduction band onset for MoS₂ of different thicknesses relative to the Fermi Energy E_F (dashed line) as obtained in STS. (Setpoint: 1.5 V, 49 pA). d Combined cross-sectional data from KPFM (blue, from a), SECM feedback with Fc mediator (black, from Fig. 3d), with DmFc mediator (red, from b) and SECM feedback with Fc mediator of a thick MoS₂ flake (green). Data are normalized to the intensity on the monolayer for relative comparison. Data from the thick flake of approx. nL = 8-layers begin on the SiO₂ substrate with, in AFM clearly resolved monolayer and bilayer areas, succeeded by a narrow transition (xL) region from second layer to a flat and extended n-layer plateau. Within the transition region, SECM data cannot be attributed to individual layers but are respectively resolution limited. TL = triple layer, CB = conduction band onset, VB = valence band onset. Background color variations indicate change of layer thickness.