无机材料学报 ›› 2023, Vol. 38 ›› Issue (6): 687-692.DOI: 10.15541/jim20220696

• 研究快报 • 上一篇    下一篇

Cl掺杂对CuI薄膜发光性能增强研究

杨颖康1(), 邵怡晴1, 李柏良1, 吕志伟1, 王路路2, 王亮君1, 曹逊1,2, 吴宇宁1, 黄荣1,3(), 杨长1()   

  1. 1.华东师范大学 物理与电子科学学院, 极化材料与器件教育部重点实验室, 上海 200241
    2.中国科学院 上海硅酸盐研究所, 上海 200050
    3. 山西大学 极端光学协同创新中心,太原 030006

Enhanced Band-edge Luminescence of CuI Thin Film by Cl-doping

YANG Yingkang1(), SHAO Yiqing1, LI Bailiang1, LÜ Zhiwei1, WANG Lulu2, WANG Liangjun1, CAO Xun1,2, WU Yuning1, HUANG Rong1,3(), YANG Chang1()   

  1. 1. Key Laboratory of Polar Materials and Devices (Ministry of Education), School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
    2. Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
    3. Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
  • Received:2022-11-21 Revised:2022-12-26 Published:2023-02-13 Online:2023-02-13
  • Contact: HUANG Rong, professor. E-mail: rhuang@ee.ecnu.edu.cn;
    YANG Chang, professor. E-mail: cyang@phy.ecnu.edu.cn
  • About author:YANG Yingkang (2002-), female, Bachelor. E-mail: 10192100516@stu.ecnu.edu.cn
  • Supported by:
    National Key Research and Development Program of China(2017YFA0303403);Shanghai Science and Technology Innovation Action Plan(19JC1416700);National Natural Science Foundation of China(62074056);National Natural Science Foundation of China(61974042);National Natural Science Foundation of China(11774092)

摘要:

宽禁带γ-CuI是一种具有优异光电和热电性能的p型透明半导体材料, 近年来受到广泛关注。但作为一种新兴材料, 其发光性能受材料缺陷影响的物理机理尚不清楚。本工作通过气相反应法制备了Cl掺杂的CuI薄膜, 采用电镜表征方法研究Cl掺杂对多晶CuI薄膜表面形貌和阴极荧光发光特性的影响, 并结合第一性原理计算探究了Cl在CuI薄膜中的主要存在形式, 以揭示Cl掺杂CuI薄膜结构与发光性能的联系。研究结果表明, 原本晶粒饱满但晶界显著的CuI薄膜掺杂Cl后呈现出致密平整的表面, 表明Cl掺杂剂改变了CuI的表面结构。相比未掺杂区域, Cl掺杂区410 nm处的荧光信号明显得到双倍增强, 而在720 nm附近的缺陷峰则略有降低, 说明Cl掺杂极大改善了CuI薄膜的发光性能。通过第一性原理计算对该现象进行理论分析, 发现引入Cl元素有效抑制了CuI中碘空位等深能级缺陷的产生, 降低了激子发生非辐射跃迁的概率, 从而改善CuI的发光性能, 这与阴极荧光的结果一致。本研究获得的掺杂CuI薄膜带边发光峰的半峰宽仅为7 nm, 表现出极高的发光单色性。这些发现有助于对卤素掺杂获得的高性能CuI基材料的理解。

关键词: CuI, Cl掺杂, 阴极荧光, 第一性原理计算

Abstract:

Wide band gap γ-CuI is a p-type transparent semiconductor with excellent optoelectronic and thermoelectric property, which has recently attracted worldwide attention. However, as an emerging material, its luminescence mechanism that is impacted by defects is rarely reported and remains obscure, limiting its further applications. In this work, Cl-doped CuI film was prepared by gas-phase reaction method. Using cathodoluminescence spectroscopy, effects of Cl doping on the surface morphology and cathodoluminescence property of CuI films were investigated in detail, and main defects of Cl presence in CuI films were explored by combining first-principle calculations, revealing relationship between structure and luminescent property of Cl-doped CuI films. These data showed Cl-doped region had a smoother surface than that of the undoped region with granular morphology, which clearly demonstrated that Cl dopant altered surface structure of the undoped region. Compared with the undoped region, the Cl dopant induced doubled fluorescence signal of band-edge emission at 410 nm, but reduced the defect peak at 720 nm, indicating that a small amount of Cl dopant brought a great luminescent improvement to CuI. The formation energy calculations of various crystal defects suggest that Cl can inhibit the formation of deep-level defects such as I vacancy in CuI and reduce the probability of non-radiative transition of excitons, which is consistent with the cathodoluminescence results. The full width at half maximum of the band-edge luminescence peak of Cl-doped CuI film is as small as 7 nm, showing extremely high luminescence monochromaticity. Therefore, the present findings deepen our understanding on how halogen doping boosts the luminescence performance of CuI-based materials.

Key words: CuI, Cl-doping, cathodoluminescence, first principle calculation

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