Thickness-dependent ultrafast charge-carrier dynamics and coherent acoustic phonon oscillations in mechanically exfoliated PdSe2 flakes
| Autor: | Yizhi Zhu, De-Kang Li, Qiannan Cui, Chunxiang Xu, Kai-Xuan Huang, Zhi-Bo Liu, Jianguo Tian, Rui Wen, Xiao-Qing Yan, Chang-Fu Huo |
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| Rok vydání: | 2021 |
| Předmět: | |
| Zdroj: | Physical Chemistry Chemical Physics. 23:20666-20674 |
| ISSN: | 1463-9084 1463-9076 |
| DOI: | 10.1039/d1cp03202j |
| Popis: | Recently, palladium diselenide (PdSe2) has emerged as a promising material with potential applications in electronic and optoelectronic devices due to its intriguing electronic and optical properties. The performance of the device is strongly dependent on the charge–carrier dynamics and the related hot phonon behavior. Here, we investigate the photoexcited–carrier dynamics and coherent acoustic phonon (CAP) oscillations in mechanically exfoliated PdSe2 flakes with a thickness ranging from 10.6 nm to 54 nm using time-resolved non-degenerate pump–probe transient reflection (TR) spectroscopy. The results imply that the CAP frequency is thickness-dependent. Polarization-resolved transient reflection (PRTR) measurements reveal the isotropic charge–carrier relaxation dynamics and the CAP frequency in the 10.6 nm region. In addition, the deformation potential (DP) mechanism dominates the generation of the CAP. Moreover, a sound velocity of 6.78 × 103 m s−1 is extracted from the variation of the oscillation period with the flake thickness and the delay time of the acoustic echo. These results provide insight into the ultrafast optical coherent acoustic phonon and optoelectronic properties of PdSe2 and may open new possibilities for PdSe2 applications in THz-frequency mechanical resonators. |
| Databáze: | OpenAIRE |
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