{"title":"二维 Te 薄膜中的声子辅助热载流子再填充","authors":"Dong-Yub Yee, Ji-Hee Kim","doi":"10.1007/s40042-024-01076-w","DOIUrl":null,"url":null,"abstract":"<p>Two-dimensional (2D) Tellurium (Te) films, emerging as a new member of a single elemental material, have gained significant attention for its potential in advanced optoelectronic devices. Here, we examined the hot carrier dynamics of Te via ultrafast transient reflection spectroscopy. The hot carrier population and relaxation processes in the second excited state are studied under resonant (1.55 eV) and nonresonant (3.1 eV) excitation conditions. A notably prolonged carrier relaxation time of 219 ps was observed under resonant excitation conditions. In contrast, hot carrier relaxation under nonresonant excitation showed an abnormal trend of rapid decrease followed by an abrupt increase around a time delay of 20 ps. This anomaly is attributed to the re-population of hot carriers, driven by decreased thermalization rates coupled with a retardation of carrier intervalley scattering within Te. We also found that the strong electron–phonon coupling in Te films promoted intervalley scattering. These results provide fundamental insights into the excited-state relaxation processes in Te, offering potential opportunities for the advancement of high-efficiency Te-based thermoelectric and electric devices.</p>","PeriodicalId":677,"journal":{"name":"Journal of the Korean Physical Society","volume":null,"pages":null},"PeriodicalIF":0.8000,"publicationDate":"2024-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Phonon-assisted hot carrier re-population in 2D Te thin films\",\"authors\":\"Dong-Yub Yee, Ji-Hee Kim\",\"doi\":\"10.1007/s40042-024-01076-w\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Two-dimensional (2D) Tellurium (Te) films, emerging as a new member of a single elemental material, have gained significant attention for its potential in advanced optoelectronic devices. Here, we examined the hot carrier dynamics of Te via ultrafast transient reflection spectroscopy. The hot carrier population and relaxation processes in the second excited state are studied under resonant (1.55 eV) and nonresonant (3.1 eV) excitation conditions. A notably prolonged carrier relaxation time of 219 ps was observed under resonant excitation conditions. In contrast, hot carrier relaxation under nonresonant excitation showed an abnormal trend of rapid decrease followed by an abrupt increase around a time delay of 20 ps. This anomaly is attributed to the re-population of hot carriers, driven by decreased thermalization rates coupled with a retardation of carrier intervalley scattering within Te. We also found that the strong electron–phonon coupling in Te films promoted intervalley scattering. These results provide fundamental insights into the excited-state relaxation processes in Te, offering potential opportunities for the advancement of high-efficiency Te-based thermoelectric and electric devices.</p>\",\"PeriodicalId\":677,\"journal\":{\"name\":\"Journal of the Korean Physical Society\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2024-05-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of the Korean Physical Society\",\"FirstCategoryId\":\"101\",\"ListUrlMain\":\"https://doi.org/10.1007/s40042-024-01076-w\",\"RegionNum\":4,\"RegionCategory\":\"物理与天体物理\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"PHYSICS, MULTIDISCIPLINARY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of the Korean Physical Society","FirstCategoryId":"101","ListUrlMain":"https://doi.org/10.1007/s40042-024-01076-w","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"PHYSICS, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
摘要
二维(2D)碲(Te)薄膜作为单一元素材料的新成员,因其在先进光电设备中的潜力而备受关注。在这里,我们通过超快瞬态反射光谱研究了碲的热载流子动力学。在共振(1.55 eV)和非共振(3.1 eV)激发条件下,研究了第二激发态的热载流子种群和弛豫过程。在共振激发条件下,观察到载流子弛豫时间明显延长至 219 ps。与此相反,非谐振激发下的热载流子弛豫呈现出一种异常趋势,即在 20 ps 的时间延迟前后,载流子弛豫迅速减小,然后突然增大。这种反常现象归因于热载流子的重新填充,其驱动力是热化率的降低以及 Te 内载流子间隔散射的延缓。我们还发现,Te 薄膜中的强电子-声子耦合促进了间隔散射。这些结果提供了对 Te 中激发态弛豫过程的基本见解,为开发基于 Te 的高效热电和电气设备提供了潜在的机会。
Phonon-assisted hot carrier re-population in 2D Te thin films
Two-dimensional (2D) Tellurium (Te) films, emerging as a new member of a single elemental material, have gained significant attention for its potential in advanced optoelectronic devices. Here, we examined the hot carrier dynamics of Te via ultrafast transient reflection spectroscopy. The hot carrier population and relaxation processes in the second excited state are studied under resonant (1.55 eV) and nonresonant (3.1 eV) excitation conditions. A notably prolonged carrier relaxation time of 219 ps was observed under resonant excitation conditions. In contrast, hot carrier relaxation under nonresonant excitation showed an abnormal trend of rapid decrease followed by an abrupt increase around a time delay of 20 ps. This anomaly is attributed to the re-population of hot carriers, driven by decreased thermalization rates coupled with a retardation of carrier intervalley scattering within Te. We also found that the strong electron–phonon coupling in Te films promoted intervalley scattering. These results provide fundamental insights into the excited-state relaxation processes in Te, offering potential opportunities for the advancement of high-efficiency Te-based thermoelectric and electric devices.
期刊介绍:
The Journal of the Korean Physical Society (JKPS) covers all fields of physics spanning from statistical physics and condensed matter physics to particle physics. The manuscript to be published in JKPS is required to hold the originality, significance, and recent completeness. The journal is composed of Full paper, Letters, and Brief sections. In addition, featured articles with outstanding results are selected by the Editorial board and introduced in the online version. For emphasis on aspect of international journal, several world-distinguished researchers join the Editorial board. High quality of papers may be express-published when it is recommended or requested.