Ultrafast van der Waals diode using graphene quantum capacitance and Fermi-level depinning.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 37467332.
- Also identified by DOI 10.1126/sciadv.adh9770 and PMC identifier 10355828.
- Licence recorded as CC BY-NC.
- Because redistribution is not established, this page shows the abstract only. Follow the links below for the full text.
Abstract
Graphene, with superior electrical tunabilities, has arisen as a multifunctional insertion layer in vertically stacked devices. Although the role of graphene inserted in metal-semiconductor junctions has been well investigated in quasi-static charge transport regime, the implication of graphene insertion at ultrahigh frequencies has rarely been considered. Here, we demonstrate the diode operation of vertical Pt/n-MoSe<sub>2</sub>/graphene/Au assemblies at ~200-GHz cutoff frequency (f<sub>C</sub>). The electric charge modulation by the inserted graphene becomes essentially frozen above a few GHz frequencies due to graphene quantum capacitance-induced delay, so that the Ohmic graphene/MoSe<sub>2</sub> junction may be transformed to a pinning-free Schottky junction. Our diodes exhibit much lower total capacitance than devices without graphene insertion, deriving an order of magnitude higher f<sub>C</sub>, which clearly demonstrates the merit of graphene at high frequencies.