@article{Liang2023, author = {Haidong Liang and Yue Zheng and Leyi Loh and Zehua Hu and Qijie Liang and Cheng Han and Michel Bosman and Wei Chen and Andrew A. Bettiol}, title = {Robust n-type doping of WSe2 enabled by controllable proton irradiation}, year = {2023}, journal = {Nano Research}, volume = {16}, number = {1}, pages = {1220-1227}, keywords = {WSe2, n-type doping, proton beam irradiation, long-time air stable, Se vacancies}, url = {https://www.sciopen.com/article/10.1007/s12274-022-4668-9}, doi = {10.1007/s12274-022-4668-9}, abstract = {Two-dimensional (2D) transition metal dichalcogenides (TMDs) are considered to be promising building blocks for the next generation electronic and optoelectronic devices. Various doping schemes and work function engineering techniques have been explored to overcome the intrinsic performance limits of 2D TMDs. However, a reliable and long-time air stable doping scheme is still lacking in this field. In this work, we utilize keV ion beams of H2+ to irradiate layered WSe2 crystals and obtain efficient n-type doping effect for all irradiated crystals within a fluence of 1 × 1014 protons·cm−2 (1e14). Moreover, the irradiated WSe2 remains an n-type semiconductor even after it is exposed to ambient conditions for a year. Localized ion irradiation with a focused beam can directly pattern on the sample to make high performance homogenous p-n junction diodes. Raman and photoluminescence (PL) spectra demonstrate that the WSe2 crystal lattice stays intact after irradiation within 1e14. We attribute the reliable electron-doping to the significant increase in Se vacancies after the proton irradiation, which is confirmed by our scanning transmission electron microscope (STEM) results. Our work demonstrates a reliable and long-term air stable n-type doping scheme to realize high-performance electronic TMD devices, which is also suitable for further integration with other 2D devices.} }