Exciton-to-Trion Conversion in Monolayer WS<sub>2</sub> under Pressure.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 40878666.
- Also identified by DOI 10.1021/acs.nanolett.5c02823 and PMC identifier 12426993.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Exciton-to-trion conversion in two-dimensional semiconductors defines the transition from an optoelectronics based on neutral bosons to one based on charged fermions, with a huge impact on the transport and spin/valley-related properties. This process has been successfully induced in field-effect transistors under gate voltage, chemically doped samples, and nonuniformly nanoscale-strained materials. Here, we study the evolution of the photoluminescence spectrum of monolayer WS<sub>2</sub> under high pressure, decoupling exciton and trion contributions by their responses to laser-power variations. We demonstrate that crystal compression drives a substrate-independent, partially reversible exciton-to-trion conversion, with trion recombination dominating the emission above 3 GPa. The observed mechanism does not rely on external charge injection but involves the pressure evolution of intrinsic doping levels within the band structure. Our results indicate that trion-based emission can be achieved by reshaping the periodic crystal potential via the modulation of interatomic interactions, offering a novel approach to the study of exciton-to-trion conversion in two-dimensional materials.