Formation of Anisotropic Polarons in Antimony Selenide

Fuente: arXiv
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Auteurs principaux: Shi, Yijie, Wang, Xi, Wang, Zhong, Zhang, Zheng, Hua, Fuyong, Chen, Chao, Hu, Chunlong, Tang, Jiang, Liang, Wenxi
Format: Preprint
Publié: 2024
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author Shi, Yijie
Wang, Xi
Wang, Zhong
Zhang, Zheng
Hua, Fuyong
Chen, Chao
Hu, Chunlong
Tang, Jiang
Liang, Wenxi
author_facet Shi, Yijie
Wang, Xi
Wang, Zhong
Zhang, Zheng
Hua, Fuyong
Chen, Chao
Hu, Chunlong
Tang, Jiang
Liang, Wenxi
contents Antimony Selenide (Sb$_2$Se$_3$) is an attractive candidate of photovoltaics with not yet satisfying efficiency. Beside defects, polaron formation originated from lattice distortion was proposed to account for trapping free carriers, and the subsequent photoexcitation dynamics and optoelectronic properties, but such a mechanism is still lack of structural observations. Here we directly track the pathways of carrier and lattice evolutions after photoexcitation through optical and electron diffraction pump-probe methods, revealing the temporal correlations between dynamics of both degrees of freedom. The observed opposite separation changes of Se2-Sb2 and Sb2-Sb1 atom pairs in a few picoseconds, and the intermediate state induced by local structural distortions lasting several tens of picoseconds, coinciding with the optical phonons population and coupling, and the trapping process of carriers, respectively, together with the analyses of modulation on diffuse scattering by the atomic displacement fields of polaron model, indicate the formation of anisotropic polarons with large size. Our findings provide carrier and structural information for helping the elucidation of polaron scenario in Sb2Se3, and probably in materials with anisotropic structure and soft lattice which are popular in developing novel optoelectronics.
format Preprint
id arxiv_https___arxiv_org_abs_2410_05155
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Formation of Anisotropic Polarons in Antimony Selenide
Shi, Yijie
Wang, Xi
Wang, Zhong
Zhang, Zheng
Hua, Fuyong
Chen, Chao
Hu, Chunlong
Tang, Jiang
Liang, Wenxi
Materials Science
Optics
Antimony Selenide (Sb$_2$Se$_3$) is an attractive candidate of photovoltaics with not yet satisfying efficiency. Beside defects, polaron formation originated from lattice distortion was proposed to account for trapping free carriers, and the subsequent photoexcitation dynamics and optoelectronic properties, but such a mechanism is still lack of structural observations. Here we directly track the pathways of carrier and lattice evolutions after photoexcitation through optical and electron diffraction pump-probe methods, revealing the temporal correlations between dynamics of both degrees of freedom. The observed opposite separation changes of Se2-Sb2 and Sb2-Sb1 atom pairs in a few picoseconds, and the intermediate state induced by local structural distortions lasting several tens of picoseconds, coinciding with the optical phonons population and coupling, and the trapping process of carriers, respectively, together with the analyses of modulation on diffuse scattering by the atomic displacement fields of polaron model, indicate the formation of anisotropic polarons with large size. Our findings provide carrier and structural information for helping the elucidation of polaron scenario in Sb2Se3, and probably in materials with anisotropic structure and soft lattice which are popular in developing novel optoelectronics.
title Formation of Anisotropic Polarons in Antimony Selenide
topic Materials Science
Optics
url https://arxiv.org/abs/2410.05155