Lowering the Schottky barrier height of G/WSSe van der Waals heterostructures by changing the interlayer coupling and applying external biaxial strain
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
Authors: Zhang, W. X.; Yin, Y.; He, C.
Abstract
Graphene-based van der Waals (vdW) heterostructures composed of two-dimensional transition metal dichalcogenides (TMDs) and graphene show great potential in the design and manufacture of field effect transistors. However, the Schottky barrier generated by the contact between metal and semiconductor hinders the conduction of electrons, so it is necessary to effectively adjust the Schottky barrier and form a low-resistance Ohmic contact. Based on first-principles calculations, graphene/WSSe (G/WSSe) heterostructures have been established and the corresponding electronic properties have been studied. Firstly, these heterostructures form an n-type Schottky contact with a SBH of 0.35 eV and a p-type Schottky contact with a SBH of 0.66 eV at their respective interfaces. In addition, the Schottky contact can be significantly adjusted by changing the interlayer coupling or applying an external biaxial strain, and an Ohmic contact could also be formed under the biaxial strain. This study not only offers a basic understanding of G/WSSe heterostructures, but also provides a reference for the application of G/WSSe heterostructures in optoelectronic and nanoelectronic devices.
Temperature-Dependent Electrical Properties of Graphitic Carbon Schottky Contacts to beta-Ga2O3
IEEE TRANSACTIONS ON ELECTRON DEVICES
Authors: Tran, Hiep N.; Le, Phuong Y.; Murdoch, Billy James; Allen, Martin W.; McConville, Christopher F.; Partridge, James G.
Abstract
Graphitic (sp(2)-rich) carbon Schottky contacts to ((2) over bar 01) beta-Ga2O3 were fabricated using sputtering and energetic ion deposition with and without the use of an oxygen plasma. As-deposited contacts exhibited room temperature effective barrier heights between 0.80 and 1.20 eV, depending on the deposition technique. After moderate heat treatment (595 K in N-2) the work function of the oxygenated graphitic contacts increased by 0.5-0.8 eV. This resulted in a permanent increase in barrier height (up to 1.6 eV) and a corresponding 3-4 orders of magnitude increase in current rectification (at +/- 3 V). The barrier heights of the heat-treated oxygenated graphitic Schottky contacts agree well with the Mott-Schottky model, suggesting an absence of Fermi level pinning at the C/beta-Ga2O3 interface.