Realizing Large-Scale, Electronic-Grade Two-Dimensional Semiconductors.
basic_science · Level V
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- Record sourced from PubMed, PMID 29360349.
- Also identified by DOI 10.1021/acsnano.7b07059.
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Abstract
Atomically thin transition metal dichalcogenides (TMDs) are of interest for next-generation electronics and optoelectronics. Here, we demonstrate device-ready synthetic tungsten diselenide (WSe<sub>2</sub>) via metal-organic chemical vapor deposition and provide key insights into the phenomena that control the properties of large-area, epitaxial TMDs. When epitaxy is achieved, the sapphire surface reconstructs, leading to strong 2D/3D (i.e., TMD/substrate) interactions that impact carrier transport. Furthermore, we demonstrate that substrate step edges are a major source of carrier doping and scattering. Even with 2D/3D coupling, transistors utilizing transfer-free epitaxial WSe<sub>2</sub>/sapphire exhibit ambipolar behavior with excellent on/off ratios (∼10<sup>7</sup>), high current density (1-10 μA·μm<sup>-1</sup>), and good field-effect transistor mobility (∼30 cm<sup>2</sup>·V<sup>-1</sup>·s<sup>-1</sup>) at room temperature. This work establishes that realization of electronic-grade epitaxial TMDs must consider the impact of the TMD precursors, substrate, and the 2D/3D interface as leading factors in electronic performance.