Anisotropic Optical And Vibrational Properties Of GeS
| Autor: | Zawadzka, Natalia, Kipczak, Łucja, Woźniak, Tomasz, Olkowska-Pucko, Katarzyna, Grzeszczyk, Magdalena, Babiński, Adam, Molas, Maciej R. |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Nanomaterials 11, 3109 (2021) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3390/nano11113109 |
| Popis: | The optical response of bulk germanium sulfide (GeS) is investigated systematically using different polarization-resolved experimental techniques, such as photoluminescence (PL), reflectance contrast (RC), and Raman scattering (RS). It is shown that while the low-temperature ($T$=5 K) optical band-gap absorption is governed by a single resonance related to the neutral exciton, the corresponding emission is dominated by the disorder/impurity- and/or phonon-assisted recombination processes. Both the RC and PL spectra are found to be linearly polarized along the armchair direction. The low and room ($T$=300 K) temperature RS spectra consist of six Raman peaks identified with the help of Density Fuctional Theory (DFT) calculations: A$^1_{\textrm{g}}$, A$^2_{\textrm{g}}$, A$^3_{\textrm{g}}$, A$^4_{\textrm{g}}$, B$^1_{\textrm{1g}}$, and B$^2_{\textrm{1g}}$, which polarization properties are studied under four different excitation energies. We found that the polarization orientations of the A$^2_{\textrm{g}}$ and A$^4_{\textrm{g}}$ modes under specific excitation energy can be useful tools to determine the GeS crystallographic directions: armchair and zigzag. Comment: 7 pages, 7 figures |
| Databáze: | arXiv |
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