Measuring the Edge Recombination Velocity of Monolayer Semiconductors.
basic_science · Level V
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- Record sourced from PubMed, PMID 28814079.
- Also identified by DOI 10.1021/acs.nanolett.7b01770.
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Abstract
Understanding edge effects and quantifying their impact on the carrier properties of two-dimensional (2D) semiconductors is an essential step toward utilizing this material for high performance electronic and optoelectronic devices. WS<sub>2</sub> monolayers patterned into disks of varying diameters are used to experimentally explore the influence of edges on the material's optical properties. Carrier lifetime measurements show a decrease in the effective lifetime, τ<sub>effective</sub>, as a function of decreasing diameter, suggesting that the edges are active sites for carrier recombination. Accordingly, we introduce a metric called edge recombination velocity (ERV) to characterize the impact of 2D material edges on nonradiative carrier recombination. The unpassivated WS<sub>2</sub> monolayer disks yield an ERV ∼ 4 × 10<sup>4</sup> cm/s. This work quantifies the nonradiative recombination edge effects in monolayer semiconductors, while simultaneously establishing a practical characterization approach that can be used to experimentally explore edge passivation methods for 2D materials.