Fig. 1: p-type doping of monolayer WSe2 using chloroform.
From: Low resistance p-type contacts to monolayer WSe2 through chlorinated solvent doping
a Schematic of chloroform-doped WSe2, illustrating the doping process and possible adsorption pathways. After fabrication, devices are left in chloroform overnight. b Benchmarking maximum p-type current (|ID,max|) vs. monolayer WSe2 channel length (Lch) at drain voltage (VDS) = -1 V at room temperature, using various contact metals and doping strategies. Circles8,37,38,39,75,76,77,78,79,80,81 mark results with no intentional doping, squares8,17,19,25,36,39,40 denote oxide-based doping (MoOx, WOx, NOx), and triangles21,23 label halide-based doping. Our results with chloroform doping (stars) achieve among the highest hole currents to date for monolayer WSe2. c Measured drain current (ID) vs. gate voltage (VGS) for monolayer WSe2 device before (black line) and after (green line) chloroform doping, reaching hole current of 203 μA/μm. Forward and backward sweeps are shown, revealing some counterclockwise hysteresis. d Raman spectra before and after chloroform doping of monolayer WSe2. e Photoluminescence (PL) spectra of monolayer WSe2 before and after chloroform doping.
