Yu Song, Han-Chun Wu, Yong Guo
We theoretically investigate negative differential resistance (NDR) in graphene double barrier resonant tunneling diodes within the Landauer-B\"{u}ttiker formalism by considering a realistic linear voltage drop. The calculated current-voltage characteristic indicates that, due to the competition between hole-to-electron transport, Klein paradox, and resonant tunneling, the NDR is substantially suppressed and only presents for appropriate structural parameters. Remarkably, the first NDR operation window is always pinned by a robust kink effect to around the Fermi energy, which may open an interesting window for designing NDR based graphene devices in a controllable way. Moreover, the peak-to-valley current ratio can be enhanced epitaxially and parabolically by opening a band gap and adjusting structural asymmetries, respectively.
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http://arxiv.org/abs/1210.2033
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