Enhanced vacuum ultraviolet photoemission from graphene nanoribbons

IF 4.5 3区材料科学 Q2 MATERIALS SCIENCE, MULTIDISCIPLINARY

2D Materials Pub Date : 2023-11-03 DOI:10.1088/2053-1583/ad047e

Martina Corso, Jorge Lobo-Checa, Andrew Weber, Ignacio Piquero-Zulaica, Zakaria Mohammed Abd El-Fattah, Patrick Le Fèvre, J. Enrique Ortega, Eugene Krasovskii

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Abstract

Abstract Photon-energy dependence of photoemission from seven-atoms-wide armchair graphene nanoribbons (GNRs) is studied experimentally and theoretically up to ℏ ω = 95 eV. A strong photon energy dependence of the normal emission from the valence band maximum (VB 1 ) is observed, sharply peaked at ℏ ω = 12 eV. The detailed analysis of the light-polarization dependence of the photoemission from VB 1 unambiguously characterizes the symmetry of the state. The experimental observations are analyzed based on ab initio one-step theory of photoemission. Off-normal emission is studied in detail and its relation to the standing-wave character of the valence band states is discussed. Excellent agreement with the earlier experiment (Senkovskiy et al 2018 2D Mater. 5 035007) is obtained. Rapid variations of the intensity with the ribbon-transverse photoelectron momentum are predicted from the ab initio theory, which are at variance with the prediction of the tight-binding rigid-wall model. These findings can help interpret angle-resolved photoemission measurements of similar systems. Moreover, the strong enhancement of the photoyield could trigger the GNR application as narrow-band photodetectors and contribute to the design of novel photocathodes for vacuum ultraviolet photodetection.

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石墨烯纳米带增强真空紫外光发射

摘要从理论上和实验上研究了7原子宽扶手型石墨烯纳米带(GNRs)的光能依赖关系。从价带最大值(vb1)观察到一个强的光子能量依赖性，在1 ω = 12 eV处达到尖峰。详细分析了VB 1光发射的光偏振依赖性，明确地表征了状态的对称性。基于从头算一步光发射理论对实验结果进行了分析。详细研究了非正常发射，并讨论了非正常发射与价带态驻波特性的关系。与早期实验(Senkovskiy et al . 2018 2D Mater. 5 035007)非常吻合。从从头算理论中预测了光电子强度随光电子横向动量的快速变化，这与紧结合刚壁模型的预测不同。这些发现有助于解释类似系统的角度分辨光发射测量。此外，光产率的显著提高可以触发GNR作为窄带光电探测器的应用，并有助于设计用于真空紫外光探测的新型光电阴极。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

2D Materials MATERIALS SCIENCE, MULTIDISCIPLINARY-

CiteScore

10.70

自引率

5.50%

发文量

138

审稿时长

1.5 months

期刊介绍： 2D Materials is a multidisciplinary, electronic-only journal devoted to publishing fundamental and applied research of the highest quality and impact covering all aspects of graphene and related two-dimensional materials.