Knowledge Bank

In this thesis, two major goals are achieved in regards to studying the electronic mobility of two-dimensional (2D) materials. The first is to establish a method that can reliably predict the electron mobility of planar materials. This was done by applying and adapting an ab-initio calculation method that uses DFT to 2D materials and testing its abilities to reproduce the electron mobilities of well-established 2D materials. We compared the calculated results for the electron mobilities of graphene, graphane, germanane, and single- and multilayered MoS2 to experiment and find good agreement. After these benchmarks were successful, we extended the method to calculate the hole mobility for the first time. Then we proceeded to predict the electron and hole mobility of 2D WS2 and WSe2. We found that WS¬2 and WSe2 have electron (hole) mobilties of 540 (116) and 1424 (435) cm2/Vs, respectively. These results outperformed the common transition metal dichalcogenides that we performed these calculations on, MoS2, by a factor of 2 and 6. We go into further analyses, such as looking at the band structures, effective masses, and scattering rates of these materials. We find that the band structures are direct gap at the K point, with WS2 and WSe2 having band gaps of 1.98 and 1.61 eV, respectively. The effective electron (hole) masses are 0.39 (0.40) and 0.44 (0.41). We find that the electron velocities give the tungsten TMDs a greater mobility than MoS2.