Scalable Substitutional Re-Doping and its Impact on the Optical and Electronic Properties of Tungsten Diselenide

Doping is the cornerstone of semiconductor technology, enabling the success of modern digital electronics. Successful realization of wafer-scale, electronic grade, intrinsic 2D TMDCs via common deposition methods is rapidly progressing, however, advances in scalable doping still remain in the “proof-of-concept” stage, delaying the large-scale fabrication of logic circuits based on extrinsic 2D semiconductors. 
This work is presenting a wafer-scale synthesis of rhenium doping of WSe2 films via MOCVD at front-end-of-line (FEOL) and back-end-of-line (BEOL) compatible temperatures. By controlling the partial pressures of the precursors, doping concentrations as low as 0.0001% can be achieved. Rhenium atoms substitutionally replace W atoms in the WSe2 lattice and introduce discrete defect levels that lie close to the conduction band minima confirming the n-type nature of the dopants. However, the transport properties of field-effect transistors degrade as a function of doping concentration which is attributed to the large binding energy of electrons due to less effective dielectric screening in monolayer 2D films.