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Pregled bibliografske jedinice broj: 806097

Exciton and charge carrier dynamics in few-layer WS2

Vega-Mayoral, Victor; Vella, Daniele; Borzda, Tetiana; Prijatelj, Matej; Tempra, Iacopo; Pogna, Eva A.A.; Dal Conte, Stefano; Topolovsek, Peter; Vujicic, Nataša; Cerullo, Giulio et al.
Exciton and charge carrier dynamics in few-layer WS2 // Nanoscale, 8 (2016), 10; 5428-5434 doi:10.1039/C5NR08384B (međunarodna recenzija, članak, znanstveni)

Exciton and charge carrier dynamics in few-layer WS2

Vega-Mayoral, Victor ; Vella, Daniele ; Borzda, Tetiana ; Prijatelj, Matej ; Tempra, Iacopo ; Pogna, Eva A.A. ; Dal Conte, Stefano ; Topolovsek, Peter ; Vujicic, Nataša ; Cerullo, Giulio ; Mihailovic, Dragan ; Gadermaier, Christoph

Nanoscale (2040-3364) 8 (2016), 10; 5428-5434

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Time dynamics ; transition metal dichalcogenides ; pump-probe

Semiconducting transition metal dichalcogenides (TMDs) have been applied as the active layer in photodetectors and solar cells, displaying substantial charge photogeneration yields. However, their large exciton binding energy, which increases with decreasing thickness (number of layers), as well as the strong resonance peaks in the absorption spectra suggest that excitons are the primary photoexcited states. Detailed time- domain studies of the photoexcitation dynamics in TMDs exist mostly for MoS2. Here, we use femtosecond optical spectroscopy to study the exciton and charge dynamics following impulsive photoexcitation in few-layer WS2. We confirm excitons as the primary photoexcitation species and find that they dissociate into charge pairs with a time constant of about 1.3 ps. The better separation of the spectral features compared to MoS2 allows us to resolve a previously undetected process: these charges diffuse through the samples and get trapped at defects, such as flake edges or grain boundaries, causing an appreciable change of their transient absorption spectra. This finding opens the way to further studies of traps in TMD samples with different defect contents.

Izvorni jezik

Znanstvena područja


Institut za fiziku, Zagreb

Autor s matičnim brojem:
Nataša Vujičić, (278444)

Časopis indeksira:

  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • Science Citation Index Expanded (SCI-EXP)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus