Covalent nitrogen doping in molecular beam epitaxy-grown and bulk WSe2

Covalent p-type doping of WSe2 thin films grown by molecular beam epitaxy and WSe2 exfoliated from bulk crystals is achieved via remote nitrogen plasma exposure. X-ray photoelectron and Raman spectroscopies indicate covalently bonded nitrogen in the WSe2 lattice as well as tunable nitrogen concentration with N-2 plasma exposure time. Furthermore, nitrogen incorporation induces compressive strain on the WSe2 lattice after N-2 plasma exposure. Finally, atomic force microscopy and scanning tunneling microscopy reveal that N-2 plasma treatment needs to be carefully tuned to avoid any unwanted strain or surface damage. (c) 2018 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license.