Phononic, photonic and excitonic properties of ∼5 nm diameter aligned CdSe nanowires

IF 4.3 3区材料科学 Q2 CHEMISTRY, MULTIDISCIPLINARY

Journal of Physics and Chemistry of Solids Pub Date : 2024-10-31 DOI:10.1016/j.jpcs.2024.112424

Vladimir V. Poborchii , Alexander A. Shklyaev , Alexander V. Fokin

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引用次数: 0

Abstract

The first work on quantum-sized CdSe nanowires (NWs) was made with NWs encapsulated in chrysotile asbestos nanotubes (asb-CdSe-NWs) in 1997. However, asb-CdSe-NWs remain under-investigated compared to widely-known solution-based CdSe NWs. Here, we study ∼5 nm diameter asb-CdSe-NWs aligned along their c-axis. Polarized optical absorption, Raman and photoluminescence spectra (OAS, RS and PLS) of asb-CdSe-NWs are examined. All spectra display a high anisotropy mainly associated with the anisotropic nearly cylindrical shape of NWs and dielectric contrast between NWs and asbestos, NW-light interaction being strong for the E//c and weak for E⊥c light polarizations. Asb-CdSe-NW E//c OAS shows ∼1.93 eV and ∼2.38 eV bands of excitonic transitions between size-quantized electronic states. RS display strong longitudinal-optical-phonon band with a weak surface-mode shoulder resonantly enhanced at the excitation wavelength corresponding to the ∼2.38 eV absorption band related to the 1Π_1/2→1Π_e transition. Acoustic radial breathing mode is observed at ∼14 cm⁻¹. Low-excitation PLS show polarized exciton emission band at ∼1.883 eV while high-excitation PLS display ∼1.836 eV biexciton emission band. The ∼47 meV biexciton binding energy is enhanced due to the low-permittivity environment. Our asb-CdSe-NW results make an important complementary contribution to the studies of CdSe NWs fabricated by a variety of different techniques.

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直径为 5 纳米的对齐硒化镉纳米线的声子、光子和激子特性

1997 年，利用封装在温石棉纳米管中的碲化镉纳米线（asb-CdSe-NWs）首次实现了量子尺寸的碲化镉纳米线（NWs）。然而，与广为人知的溶液基 CdSe 纳米线相比，asb-CdSe-NWs 的研究仍然不足。在这里，我们研究了直径为 5 nm、沿其 c 轴排列的 asb-CdSe-NW。我们研究了asb-CdSe-NWs的偏振光吸收、拉曼和光致发光光谱（OAS、RS和PLS）。所有光谱都显示出高度各向异性，这主要与各向异性的近圆柱形 NWs 以及 NWs 和石棉之间的介电对比有关，NW 与光的相互作用在 E//c 偏振时很强，而在 E⊥c 偏振时很弱。Asb-CdSe-NW E//c OAS 显示出尺寸均衡电子态之间的激子跃迁带 ∼1.93 eV 和 ∼2.38 eV。在与 1Π1/2→1Πe 转变相关的 ∼2.38 eV 吸收带相对应的激发波长处，RS 显示出强纵向光-声子带和一个弱表面模式肩共振增强。在 ∼14 cm-1 处观察到声径向呼吸模式。低激发 PLS 在 ∼1.883 eV 处显示出偏振激子发射带，而高激发 PLS 则显示出 ∼1.836 eV 的双激子发射带。在低容限环境中，47 meV 的双激子结合能得到了提高。我们的asb-CdSe-NW结果为通过各种不同技术制备的硒化镉薄膜的研究做出了重要的补充贡献。

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来源期刊

Journal of Physics and Chemistry of Solids 工程技术-化学综合

CiteScore

7.80

自引率

2.50%

发文量

605

审稿时长

40 days

期刊介绍： The Journal of Physics and Chemistry of Solids is a well-established international medium for publication of archival research in condensed matter and materials sciences. Areas of interest broadly include experimental and theoretical research on electronic, magnetic, spectroscopic and structural properties as well as the statistical mechanics and thermodynamics of materials. The focus is on gaining physical and chemical insight into the properties and potential applications of condensed matter systems. Within the broad scope of the journal, beyond regular contributions, the editors have identified submissions in the following areas of physics and chemistry of solids to be of special current interest to the journal: Low-dimensional systems Exotic states of quantum electron matter including topological phases Energy conversion and storage Interfaces, nanoparticles and catalysts.