Excitation Photon Energy-Dependent Carrier Multiplication in Graphite

IF 9.6 1区化学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

ACS Materials Letters Pub Date : 2024-11-19 DOI:10.1021/acsmaterialslett.4c0113310.1021/acsmaterialslett.4c01133

Shucai Xia, Huizhi Xie, Jialong Li, Weiqing Zhang, Zefeng Ren, Dongxu Dai, Xueming Yang and Chuanyao Zhou*,

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Abstract

Due to the enhanced carrier–carrier interaction, carrier multiplication (CM) in graphitic materials is efficient and exhibits strong wavelength dependence. However, there is still a lack of direct evidence for excitation photon energy-dependent impact ionization, the origin of CM. In this work, time- and angle-resolved photoelectron spectroscopy has been used to measure the electron dynamics in graphite. We find the unusual preceding growth of electron signal in 0–0.35 eV compared with that in 0.35–0.70 eV and 0.70–1.05 eV during the absorption of UV (3.10 eV) pulses, unambiguously suggesting the occurrence of impact ionization. Such phenomena are much less significant under IR (1.55 eV) excitation. Taking into account the electron–phonon scatterings during the electron thermalization, the CM value is calculated to be 2.0 and 1.4 under UV and IR excitation, respectively. This work provides direct evidence for excitation photon energy-dependent impact ionization, which will benefit the potential applications of graphitic materials.

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来源期刊

ACS Materials Letters MATERIALS SCIENCE, MULTIDISCIPLINARY-

CiteScore

14.60

自引率

3.50%

发文量

261

期刊介绍： ACS Materials Letters is a journal that publishes high-quality and urgent papers at the forefront of fundamental and applied research in the field of materials science. It aims to bridge the gap between materials and other disciplines such as chemistry, engineering, and biology. The journal encourages multidisciplinary and innovative research that addresses global challenges. Papers submitted to ACS Materials Letters should clearly demonstrate the need for rapid disclosure of key results. The journal is interested in various areas including the design, synthesis, characterization, and evaluation of emerging materials, understanding the relationships between structure, property, and performance, as well as developing materials for applications in energy, environment, biomedical, electronics, and catalysis. The journal has a 2-year impact factor of 11.4 and is dedicated to publishing transformative materials research with fast processing times. The editors and staff of ACS Materials Letters actively participate in major scientific conferences and engage closely with readers and authors. The journal also maintains an active presence on social media to provide authors with greater visibility.