AVS 65th International Symposium & Exhibition
    Electronic Materials and Photonics Division Thursday Sessions
       Session EM-ThP

Paper EM-ThP19
Properties of WSe2 Thin Films Grown by Molecular Beam Epitaxy

Thursday, October 25, 2018, 6:00 pm, Room Hall B

Session: Electronic Materials and Photonics Division Poster Session
Presenter: Stephen McDonnell, University of Virginia
Authors: P. Litwin, University of Virginia
K.M. Freedy, University of Virginia
T. Zhu, University of Virginia
M. Zebarjadi, University of Virginia
S. McDonnell, University of Virginia
Correspondent: Click to Email
The synthesis of high quality transition metal dichalcogenide (TMD) films is of significant interest for potential applications in nanoelectronic and thermoelectric devices. Molecular beam epitaxy (MBE) is a promising route, providing fine control over growth conditions. To further understand the growth conditions on film quality, we study the effect of processing conditions on the resultant material quality. MBE is used to synthesize bilayer WSe2and it is shown using in-vacuo x-ray photoelectron spectroscopy (XPS) that the process conditions can directly influence the resultant chemistry and electronic structure. Specifically, we show that the initial nucleation conditions are critical to achieving repeatable and high-quality WSe2. Our combination of MBE and in-situ XPS studies show that WSe2chemistry can be controlled through processing conditions. We also use ex-situ characterization to determine properties such as cross-plane resistance and Seebeck coefficient. It is shown that Ni and Au contacts result in negative and positive Seeback coefficients respectively. Furthermore, Ni contacts are found to degrade over time.Presented will be our results showing the process control of WSe2chemistry. Also shown will be the impact of these changes on device relevant properties, such as resistance and Seebeck coefficient.