Tracking electronic band alignment across 2D bridge-channel MoS2 during charge transport

Commanding charge carrier diffusion in semiconducting channels requires the precise and realistic experimental realization of electronic energy band alignments at the interfaces and within the channels. We have demonstrated a non-contact and direct way to accurately probe the energy band bending at nanoscale spatial precision on MoS2 flakes laid on gold electrodes by mapping the surface potential landscape at non-equilibrium conditions during carrier injection. By systematically varying the charge carrier injection, the contrast gradient in surface potential profiles is studied along the MoS2 channel. Corresponding interfacial parameters, such as surface electric field ( xi), built-in potential (psi(bi)), and space charge density ( sigma), are experimentally determined.