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October 1, 2019 | 2:30 p.m. - 3:45 p.m.
Category: Seminar
Location: Physics #245
Cost: Free
Audience: Academic Staff, Alumni, Current Graduate Students, Current Undergraduate Students, Faculty

Kraig Andrews (Wayne State University)

Abstract:

We report a new contact engineering method to minimize the Schottky barrier height (SBH) of MoS2 field-effect transistors (FETs) by using MoSe2 as an interlayer. We demonstrate that the addition of an ultrathin MoSe2 interlayer between the MoS2 channel and Ti electrodes reduces the SBH at the contacts by a factor of 4 from ~ 100 meV to ~ 25 meV, contact resistivity by about 60 times from ~6×10−5Ω 𝑐𝑚2 to ~1×10−6Ω 𝑐𝑚2, and current transfer length by a factor of 6 from ~ 425 nm to ~ 70 nm. The drastic reduction of SBH can be attributed to the synergy of Fermi level pinning close to the conduction band edge of the MoSe2 interlayer and the conduction band offset between the MoSe2 interlayer and MoS2 channel. As a result, the two-terminal effective mobility also improves from ~ 30-40 cm2V-1s-1 to 50-60 cm2V-1s-1 at room temperature.

For more information about this event, please contact Boris Nadgorny at 313-577-2757 or nadgorny@physics.wayne.edu.