| AVS 65th International Symposium & Exhibition | |
| 2D Materials Focus Topic | Wednesday Sessions |
| Session 2D+MN+NS+SS-WeA |
| Session: | IoT Session: Surface Chemistry, Functionalization, Bio and Sensor Applications |
| Presenter: | Anna Hoffman, University of Tennessee Knoxville |
| Authors: | A.N. Hoffman, University of Tennessee Knoxville M.G. Stanford, University of Tennessee Knoxville C. Zhng, University of Tennessee Knoxville I. Ivanon, Oak Ridge National Laboratory A.D. Oyedele, University of Tennessee Knoxville D.G. Mandrus, University of Tennessee Knoxville L. Liang, Oak Ridge National Laboratory B.G. Sumpter, Oak Ridge National Laboratory K. Xiao, Oak Ridge National Laboratory P.D. Rack, University of Tennessee Knoxville |
| Correspondent: | Click to Email |
Interest in transition metal dichalcogenides (TMDs) for opto-electronic applications has been growing recently due to their unique properties and layered structure. Surface science and DFT simulations have corroborated p-type doping and n-type suppression of O2 and H2O adsorption in TMDs however, electrical characterization has not been fully investigated. This presentation will demonstrate the reversible suppression of n-type conduction in ambi-polar WSe2 via water adsorption, which logically has a larger impact as the WSe2 thickness decreases. Additionally, we observe a reversible and irreversible n-type suppression and p-type doping which we attribute to H2O adsorption and isoelectronic oxygen chemisorption, respectively, at chalcogen vacancies during long term aging in atmosphere over 6 weeks. Finally, controlled oxygen plasma exposure is utilized to oxidize and p-type dope WSe2. We will overview our device fabrication and electrical testing procedure, and transfer characteristics for our as-fabricated devices for various WSe2 thicknesses in air and in vacuum will be illustrated. Long-term (6 week) electrical measurements in both air and vacuum are compared to the as-fabricated devices. Finally, complementary atomic force microscopy and Raman Spectroscopy are used to characterize the devices