Fairbrother, Andrew; Izquierdo Roca, Victor; Fontané, Xavier; Ibanez Sabate, MariaIST Austria ; Cabot, Andreu; Saucedo, Edgardo; Pérez Rodríguez, Alejandro
Near-resonant Raman scattering measurements of zinc sulfide nanoparticles and thin films have been made and correlated to grain and particle size, respectively, using a 325 nm wavelength excitation source. The area ratios between the first, second, and third order peaks of ZnS identified as the T 2(LO) mode decrease with increasing ZnS grain size. This is an effect attributed to changes in the bandgap energy from quantum confinement due to the varying grain size between the films/particles, as noted by a shift in the room temperature photoluminescence emission corresponding to the free exciton emission energy. While Raman scattering spectroscopy is typically limited to identification of phases and their crystalline properties, it is possible to attain more than such straightforward information by calibrating the spectral features to variations between sets of samples. These results open the possibility of making a quantitative grain size estimation in ZnS thin films and nanostructures, as well as in other material systems where ZnS may be expected as a secondary phase, such as Cu2ZnSnS4. Additionally, more commonly used excitation wavelengths for Raman scattering, such as 514 and 532 nm, are shown to be of limited use in characterizing ZnS thin films due to the extremely low Raman scattering efficiency of ZnS in films with sub-micron thicknesses.
This research was supported by the People Programme (Marie Curie Actions) of the European Union's Seventh Framework Programme under REA grant agreement number 269167 (PVICOKEST) and the Spanish Ministerio de Economía y Competividad (MINECO) under KEST-PV (ref. ENE2010- 121541-C03-01/02). Authors from IREC belong to the M-2E (Electronic Materials for Energy) Consolidated Research Group and the XaRMAE Network of Excellence on Materials for Energy of the “Generalitat de Catalunya”. A. Fairbrother thanks the MINECO for support via the FPU program (FPU12/05508), V. Izquierdo for the Juan de la Cierva program (JCI-2011-10782), and E. Saucedo for the Ramón y Cajal program (RYC-2011-09212).
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Fairbrother A, Izquierdo Roca V, Fontané X, et al. ZnS grain size effects on near-resonant Raman scattering: Optical non-destructive grain size estimation. CrystEngComm. 2014;16(20):4120-4125. doi:10.1039/c3ce42578a
Fairbrother, A., Izquierdo Roca, V., Fontané, X., Ibáñez, M., Cabot, A., Saucedo, E., & Pérez Rodríguez, A. (2014). ZnS grain size effects on near-resonant Raman scattering: Optical non-destructive grain size estimation. CrystEngComm. Royal Society of Chemistry. https://doi.org/10.1039/c3ce42578a
Fairbrother, Andrew, Victor Izquierdo Roca, Xavier Fontané, Maria Ibáñez, Andreu Cabot, Edgardo Saucedo, and Alejandro Pérez Rodríguez. “ZnS Grain Size Effects on Near-Resonant Raman Scattering: Optical Non-Destructive Grain Size Estimation.” CrystEngComm. Royal Society of Chemistry, 2014. https://doi.org/10.1039/c3ce42578a.
A. Fairbrother et al., “ZnS grain size effects on near-resonant Raman scattering: Optical non-destructive grain size estimation,” CrystEngComm, vol. 16, no. 20. Royal Society of Chemistry, pp. 4120–4125, 2014.
Fairbrother A, Izquierdo Roca V, Fontané X, Ibáñez M, Cabot A, Saucedo E, Pérez Rodríguez A. 2014. ZnS grain size effects on near-resonant Raman scattering: Optical non-destructive grain size estimation. CrystEngComm. 16(20), 4120–4125.
Fairbrother, Andrew, et al. “ZnS Grain Size Effects on Near-Resonant Raman Scattering: Optical Non-Destructive Grain Size Estimation.” CrystEngComm, vol. 16, no. 20, Royal Society of Chemistry, 2014, pp. 4120–25, doi:10.1039/c3ce42578a.