Optical, morphological and structural characterization of Er 3 + -Bi 3+ co-doped PbS nanocrystals grown by chemical bath
| Autor: | R. Gutiérrez Pérez, L. A. Chaltel Lima, G. Hernández Téllez, A. Moreno Rodríguez, O. Portillo Moreno, R. Palomino Merino, E. Rubio Rosas, M.N. Márquez Specia |
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| Rok vydání: | 2018 |
| Předmět: |
Potential well
Materials science Scanning electron microscope Band gap Doping Analytical chemistry 02 engineering and technology 010402 general chemistry 021001 nanoscience & nanotechnology 01 natural sciences Atomic and Molecular Physics and Optics 0104 chemical sciences Electronic Optical and Magnetic Materials symbols.namesake Absorption band symbols Electrical and Electronic Engineering Fourier transform infrared spectroscopy Absorption (chemistry) 0210 nano-technology Raman spectroscopy |
| Zdroj: | Optik. 162:182-195 |
| ISSN: | 0030-4026 |
| Popis: | PbS nanocrystals co-doped simultaneously in Er 3+ and Bi 3+ solutions were grown and the modification of morphological, structural and some optical properties was investigated. The thicknesses of the undoped and doped PbS films were in the ∼560–400 nm range. The morphological changes of the nanocrystals were analyzed using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) techniques. Fourier transform infrared spectroscopy ((FT-IR)) spectra showed a broad absorption band located at ∼3500 cm −1 attributed to stretching of the –OH groups and a sharp band at ∼1384 cm -1 owing to stretching vibrations mode of C O 3 2 - ions. X-ray diffraction displayed a cubic phase in all films and grain size (GS) of the undoped and doped samples were ∼33 and ∼21–17 nm, respectively. The films showed stress, a typical behavior of doped nanocrystals displaying residual strain. The absorbance spectra of PbS film exhibited four absorption bands located at ∼251 nm (∼4.9 eV), ∼610 nm (∼2.0 eV), ∼668 nm (∼1.8 eV) and ∼830 nm (∼1.4 eV) due to strong confinement effect and ∼446 nm (∼2.7 eV), ∼478 nm (∼2.5 eV) corresponding to 4 F 7/2 → 4 I 5/2 , 4 F 3/2 → 4 I 15/2 ( f → f ) transitions of Er 3+ ions. Sharp bands were found at ∼287 nm (∼4.3 eV) and 366 nm (∼3.38 eV), corresponding to transitions of Bi 3+ ions. The band gap energy of films showed a shift in the ∼0.9–1.2 eV range. Raman spectra showed two bands located at ∼450 cm −1 due to the first overtone of the longitudinal optical (LO) phonon (2LO) and a band observed at ∼200 cm −1 which was attributed to the LO (Γ) phonon. A kinetic mechanism using the free energy changes Gibbs is proposed. |
| Databáze: | OpenAIRE |
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