Gate-Tunable Graphene-WSe<sub>2</sub> Heterojunctions at the Schottky-Mott Limit.

LaGasse, Samuel W; Dhakras, Prathamesh; Watanabe, Kenji; Taniguchi, Takashi; Lee, Ji Ung · Adv Mater · 2019

basic_science · Level V

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Abstract

Metal-semiconductor interfaces, known as Schottky junctions, have long been hindered by defects and impurities. Such imperfections dominate the electrical characteristics of the junction by pinning the metal Fermi energy. Here, a graphene-WSe<sub>2</sub> p-type Schottky junction, which exhibits a lack of Fermi level pinning, is studied. The Schottky junction displays near-ideal diode characteristics with large gate tunability and small leakage currents. Using a gate electrostatically coupled to the WSe<sub>2</sub> channel to tune the Schottky barrier height, the Schottky-Mott limit is probed in a single device. As a special manifestation of the tunable Schottky barrier, a diode with a dynamically controlled ideality factor is demonstrated.