Physica E-low-dimensional Systems & Nanostructures最新文献_第2页

Effect of electric field, strain, and their synergistic interaction on Schottky barrier tuning and electronic structures in 2D TaSe2/SeMoSiP2 heterostructures 电场、应变及其协同作用对二维TaSe2/SeMoSiP2异质结构中肖特基势垒调谐和电子结构的影响

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2026-01-04 DOI: 10.1016/j.physe.2025.116454

Chen Du, You Xie, Yi-Xuan Wu, Xue Cao, Su-Fang Wang, Li-Yong Chen, Tao Zhang

The ubiquitous Schottky barrier (SB) formation at metal-semiconductor interfaces remains a fundamental challenge that degrades device performance, while achieving Ohmic contacts in 2D heterostructures could revolutionize nanoelectronics. Herein, we employ first-principles calculations to systematically investigate the SB modulation mechanisms in 2D TaSe₂/SeMoSiP₂ heterostructures. Four energetically stable configurations (Ⅰ-Ⅳ) are identified, exhibiting distinct contact characteristics: 1T-phase-based types Ⅰ and Ⅱ form n-type Schottky contacts with barriers of 0.38/0.25 eV, whereas 2H-phase-based types Ⅲ and Ⅳ demonstrate p-type behavior (0.42/0.31 eV barriers). Notably, external stimuli induce remarkable transitions: (1) ±0.6 V/Å electric fields enable reversible n↔p contact-type switching, achieving ideal Ohmic contacts at critical field strengths; (2) ±10 % biaxial strain triggers universal Ohmic transitions via bandgap renormalization, particularly effective in type Ⅱ under compression; and (3) synergistic field-strain modulation amplifies band-edge shifts by 300 % compared to individual stimuli, with compressive strain (−4 %) plus negative field (−0.4 V/Å) inducing VBM-Fermi level crossing, while tensile strain (6 %) with positive field (0.5 V/Å) drives CBM crossing. These findings establish a comprehensive dual-regulation paradigm for tailored SB engineering, providing fundamental insights and practical guidelines for designing high-performance 2D nanoelectronics devices.

在金属-半导体界面上普遍存在的肖特基势垒（SB）形成仍然是降低器件性能的基本挑战，而在二维异质结构中实现欧姆接触可能会彻底改变纳米电子学。在此，我们采用第一性原理计算系统地研究了二维TaSe2/SeMoSiP2异质结构中的SB调制机制。确定了四种能量稳定构型（Ⅰ-Ⅳ），表现出不同的接触特征：1t相型Ⅰ和Ⅱ形成n型肖特基接触，势垒为0.38/0.25 eV，而2h相型Ⅲ和Ⅳ表现为p型行为（势垒为0.42/0.31 eV）。值得注意的是，外部刺激诱导显著的过渡：(1)±0.6 V/Å电场使可逆的n↔p接触型切换成为可能，在临界场强下实现理想的欧姆接触；(2)±10%双轴应变通过带隙重整化触发普适欧姆跃迁，在Ⅱ型压缩下特别有效；(3)与单个刺激相比，协同场-应变调制将带边位移放大300%，压缩应变（- 4%）加负场（- 0.4 V/Å）诱导vbm -费米能级交叉，而拉应变（6%）加正场（0.5 V/Å）驱动CBM交叉。这些发现为定制SB工程建立了全面的双调控范式，为设计高性能2D纳米电子器件提供了基本见解和实用指南。

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引用次数: 0

Optically tunable quaternary 2D heterostructures for fast, simulation-driven nanoelectronic reconfiguration 用于快速、模拟驱动的纳米电子重构的光学可调谐的二维四元异质结构

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-30 DOI: 10.1016/j.physe.2025.116457

Arash Vaghef-Koodehi

We present a comprehensive simulation-based study of a quaternary van der Waals heterostructure—Graphene/WSe₂/MoTe₂/In₂Se₃—engineered for fully optical, voltage-free reconfiguration of nanoelectronic logic. Optical power densities between 1 μW/cm² and 100 μW/cm² were applied consistently across all simulations, inducing reversible threshold-voltage shifts up to 3.5 V over a broadband spectral range (400–1300 nm). Coupled Schrödinger–Poisson and drift–diffusion calculations reveal carrier dynamics governed by photodoping and ferroelectric charge trapping, yielding responsivity ≈2.5 A/W (at 650 nm) and sub-100 ns switching times. Layer-thickness optimization (WSe₂: 1.2 nm, MoTe₂: 0.9 nm) ensures balanced optical absorption and carrier transit, minimizing total power consumption near 15 μW/cm² illumination. Thermal reliability tests within 250–400 K show negligible drift in V_TH (0.8 mV/K) and responsivity (0.2 %/K). These findings establish design principles for high-speed, optically driven logic architectures, offering promising pathways toward simulation-based reconfigurable 2D nanoelectronics and neuromorphic photogating devices.

我们提出了一种基于模拟的四元范德华异质结构——石墨烯/WSe2/MoTe2/ in2se3——的综合研究，该异质结构用于纳米电子逻辑的全光学、无电压重构。在所有模拟中，光功率密度在1 μW/cm2和100 μW/cm2之间，在宽带光谱范围（400-1300 nm）内诱导高达3.5 V的可逆阈值电压偏移。耦合Schrödinger-Poisson和漂移扩散计算揭示了由光掺杂和铁电电荷捕获控制的载流子动力学，产生响应率≈2.5 A/W （650 nm）和低于100 ns的开关时间。层厚优化（WSe2: 1.2 nm, MoTe2: 0.9 nm）确保了平衡的光吸收和载流子传输，将总功耗降至15 μW/cm2附近。在250-400 K范围内的热可靠性测试显示VTH （0.8 mV/K）和响应度（0.2% /K）的漂移可以忽略不计。这些发现建立了高速、光驱动逻辑架构的设计原则，为基于仿真的可重构二维纳米电子学和神经形态光控器件提供了有希望的途径。

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引用次数: 0

Broadband perfect absorber based on graphene-silicon Mie heterojunctions for cancer cell detection 基于石墨烯-硅Mie异质结的宽带完美吸收剂用于癌细胞检测

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-29 DOI: 10.1016/j.physe.2025.116456

Qingbing Yang , Lili Zeng , Minghua Wang , Bingwei Guo , Yufan Deng , Shuxin Xu , Boxun Li

In this paper, a composite architecture is pioneered, comprising a three-layer heterostructure of patterned graphene and silicon cylinder-embedded dielectric. To leverage strong Mie resonances triggered by embedded silicon pillars, an octagonal–cross–octagonal stacked graphene configuration is introduced. The key innovation is the demonstration of synergistic triple-mode coupling among Mie resonance, plasmonic mode, and Fabry–Pérot cavity resonance in the terahertz regime, which seamlessly fuses multiple discrete absorption peaks into a broadband spectrum. The absorber achieves an unprecedented absorption exceeding 96 % within 6.22–11.62 THz, setting a bandwidth record of 5.40 THz (fractional bandwidth of 60.5 %), with absorption over 98 % sustained across a 1.86 THz sub-band. Dynamic modulation of absorption characteristics is readily attainable by adjusting graphene's Fermi level and relaxation time. The absorption remains robust for incident angles up to 22.92°owing to its rotationally symmetric design, effectively eliminating angle dependence. Pushing the frontier further, this structure is innovatively harnessed for biomedical sensing, where the redshift of resonance peaks enables clear differentiation between healthy cells and breast cancer cells. Traditional methods primarily rely on monitoring the shifts of resonance peaks or dips, while this study, leveraging the field enhancement properties of the structure, further proposes a new sensitivity metric based on changes in absorption intensity for dual verification. It is this dual mechanism that ultimately achieves a high sensitivity of 4.29 THz/RIU and an intensity sensitivity of 55.89 %, opening up a new pathway for terahertz biosensing applications. This work transcends the longstanding trade-off between bandwidth and tunability in conventional terahertz absorbers, opening up a new pathway for terahertz biosensing applications.

本文开创了一种复合结构，包括图像化石墨烯和硅圆柱体嵌入介质的三层异质结构。为了利用嵌入硅柱引发的强Mie共振，引入了八角形-交叉八角形堆叠石墨烯结构。关键的创新是演示了在太赫兹频段中Mie共振、等离子体模式和fabry - psamot腔共振之间的协同三模耦合，将多个离散吸收峰无缝融合到宽带频谱中。该吸收器在6.22-11.62太赫兹范围内实现了前所未有的超过96%的吸收率，创造了5.40太赫兹（分数带宽为60.5%）的带宽记录，在1.86太赫兹子带内吸收率持续超过98%。通过调整石墨烯的费米能级和弛豫时间，可以很容易地实现吸收特性的动态调制。由于其旋转对称设计，在入射角高达22.92°的情况下，吸收仍然保持稳健，有效地消除了角度依赖性。进一步推动前沿，这种结构被创新地用于生物医学传感，其中共振峰的红移可以明确区分健康细胞和乳腺癌细胞。传统方法主要依赖于监测共振峰或低谷的位移，而本研究利用结构的场增强特性，进一步提出了一种基于吸收强度变化的新的灵敏度度量，用于双重验证。正是这种双重机制最终实现了4.29 THz/RIU的高灵敏度和55.89%的强度灵敏度，为太赫兹生物传感应用开辟了新的途径。这项工作超越了传统太赫兹吸收器在带宽和可调性之间的长期权衡，为太赫兹生物传感应用开辟了一条新的途径。

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引用次数: 0

Electronic structure and light-harvesting efficiency of Janus XSO (X = Sn, Ge) monolayers Janus XSO （X = Sn, Ge）单层膜的电子结构与光捕获效率

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-23 DOI: 10.1016/j.physe.2025.116453

Bill D. Aparicio Huacarpuma , Muhammad Irfan , Carlos A. Vilca Huayhua , Fábio L. Lopes de Mendonça , Carlos M.O. Bastos , Alexandre C. Dias , Luiz A. Ribeiro Junior

The urgent global demand for clean and efficient energy has intensified the search for novel low-dimensional materials with photovoltaic potential. Two-dimensional (2D) materials, particularly Janus materials, are emerging as promising candidates for solar cell applications owing to their electronic properties. However, the literature lacks studies that analyze the impact of excitons on their optical properties and power conversion efficiency (PCE) for such devices. In this work, we perform a comprehensive first-principles investigation of the structural, thermodynamic, electronic, and optical properties of 2D Janus XSO (

X =

Sn, Ge) monolayers, analyzing the impact of excitonic effects on photovoltaic devices. Both systems are identified as direct-gap semiconductors, with band gaps of 0.86 eV and 0.59 eV at the PBE level, increasing to 1.74 eV and 1.52 eV within the HSE06 functional, respectively. Their optical response, evaluated through a Wannier basis tight-binding Hamiltonian combined with the Bethe–Salpeter equation, reveals pronounced excitonic effects, with binding energies of 315 meV for SnSO and 256 meV for GeSO. The photovoltaic performance, assessed via the Shockley–Queisser limit, yields theoretical power conversion efficiencies of up to 32.46 %. These results demonstrate that 2D Janus SnSO and GeSO monolayers are promising candidates for next-generation solar energy technologies, combining suitable band gaps with intense light–matter interactions.

全球对清洁和高效能源的迫切需求，加强了对具有光伏潜力的新型低维材料的研究。二维（2D）材料，特别是Janus材料，由于其电子特性，正在成为太阳能电池应用的有希望的候选者。然而，文献中缺乏分析激子对此类器件光学性质和功率转换效率（PCE）影响的研究。在这项工作中，我们对二维Janus XSO （X= Sn, Ge）单层的结构、热力学、电子和光学性质进行了全面的第一性原理研究，分析了激子效应对光伏器件的影响。这两种系统都被确定为直接隙半导体，在PBE水平上的带隙分别为0.86 eV和0.59 eV，在HSE06功能范围内分别增加到1.74 eV和1.52 eV。通过结合Bethe-Salpeter方程的万尼尔基紧密结合哈密顿量来评估它们的光学响应，揭示了明显的激子效应，SnSO的结合能为315 meV， GeSO的结合能为256 meV。光伏性能，通过Shockley-Queisser极限评估，产生高达32.46%的理论功率转换效率。这些结果表明，2D Janus SnSO和GeSO单层膜结合了合适的带隙和强烈的光-物质相互作用，是下一代太阳能技术的有希望的候选者。

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引用次数: 0

Structural and electronic properties, quantum capacitance of Pt-adsorbed Zr2CT2 (T = O, S, Se, F, Cl, Br, I) as supercapacitor electrode materials: First-principle predictions pt吸附Zr2CT2 （T = O， S, Se， F, Cl, Br， I）作为超级电容器电极材料的结构和电子性质、量子电容：第一性原理预测

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-22 DOI: 10.1016/j.physe.2025.116452

Peng-Fei Liu , Xiao-Hong Li , Rui-Zhou Zhang , Hong-Ling Cui

The electronic properties and quantum capacitance of Pt-adsorbed Zr₂CT₂ (T = O, S, Se, F, Cl, Br, I) are explored by density functional theory (DFT). The most stable adsorption configurations are confirmed for all systems. Compared to pristine Zr₂CO₂, Pt adsorption causes the increase of band gap. Pt-Zr₂CO₂ exhibits an indirect bandgap semiconductor of 1.36 eV, while other systems show metallic behavior. Pt donates electrons to substrate material for Pt-Zr₂CO₂ and gains electrons from the substrate for other systems, especially Pt atom in Pt-Zr₂CF₂ gains the most electrons (0.61e). Pt-Zr₂CT₂ with group VII elements are anode materials in whole voltage, with the maximum surface storage charge (Q) at negative bias ranging from 69.58 to 93.05 μC/cm² at aqueous system. Pt-Zr₂CT₂ (T = O, S, Se) are cathode materials in ionic/organic system. Pt-Zr₂CT₂ with mixed terminations are all anode materials in whole voltage.

利用密度泛函理论（DFT）研究了pt吸附Zr2CT2 （T = O， S, Se， F, Cl, Br， I）的电子性质和量子电容。确定了所有体系的最稳定吸附构型。与原始Zr2CO2相比，Pt吸附导致带隙增大。Pt-Zr2CO2表现出1.36 eV的间接带隙半导体，而其他体系表现出金属行为。在Pt- zr2co2体系中，Pt原子向衬底材料提供电子，在其他体系中，Pt原子从衬底获得电子，特别是Pt- zr2cf2中的Pt原子获得电子最多（0.61e）。含VII族元素的Pt-Zr2CT2是全电压下的正极材料，在水溶液体系中负偏压下的最大表面存储电荷Q值在69.58 ~ 93.05 μC/cm2之间。Pt-Zr2CT2 （T = O， S, Se）是离子/有机体系中的正极材料。混合端子Pt-Zr2CT2在全电压下均为正极材料。

{"title":"Structural and electronic properties, quantum capacitance of Pt-adsorbed Zr2CT2 (T = O, S, Se, F, Cl, Br, I) as supercapacitor electrode materials: First-principle predictions","authors":"Peng-Fei Liu , Xiao-Hong Li , Rui-Zhou Zhang , Hong-Ling Cui","doi":"10.1016/j.physe.2025.116452","DOIUrl":"10.1016/j.physe.2025.116452","url":null,"abstract":"<div><div>The electronic properties and quantum capacitance of Pt-adsorbed Zr<sub>2</sub>CT<sub>2</sub> (T = O, S, Se, F, Cl, Br, I) are explored by density functional theory (DFT). The most stable adsorption configurations are confirmed for all systems. Compared to pristine Zr<sub>2</sub>CO<sub>2</sub>, Pt adsorption causes the increase of band gap. Pt-Zr<sub>2</sub>CO<sub>2</sub> exhibits an indirect bandgap semiconductor of 1.36 eV, while other systems show metallic behavior. Pt donates electrons to substrate material for Pt-Zr<sub>2</sub>CO<sub>2</sub> and gains electrons from the substrate for other systems, especially Pt atom in Pt-Zr<sub>2</sub>CF<sub>2</sub> gains the most electrons (0.61e). Pt-Zr<sub>2</sub>CT<sub>2</sub> with group VII elements are anode materials in whole voltage, with the maximum surface storage charge (Q) at negative bias ranging from 69.58 to 93.05 μC/cm<sup>2</sup> at aqueous system. Pt-Zr<sub>2</sub>CT<sub>2</sub> (T = O, S, Se) are cathode materials in ionic/organic system. Pt-Zr<sub>2</sub>CT<sub>2</sub> with mixed terminations are all anode materials in whole voltage.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116452"},"PeriodicalIF":2.9,"publicationDate":"2025-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

First-principles investigation of vacancy and doping effects on the magnetic and electronic properties of monolayer β-MoSi2N4 空位和掺杂对单层β-MoSi2N4磁性和电子性能影响的第一性原理研究

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-22 DOI: 10.1016/j.physe.2025.116447

Yi Peng , Fangyuan Li , Qianqian Zhu , Juexian Cao

This study comprehensively examines how point defects (vacancies and substitutional doping) affect the magnetic, and electronic characteristics of β-MoSi₂N₄ monolayers using first-principles calculations. The analysis reveals that β-MoSi₂N₄ monolayers with vacancy defects V_Mo or V_N3Si display non-magnetic behavior, while V_N1, V_N2, V_NSi3, and V_Si introduce magnetic properties, with the magnetic moments primarily stemming from nearby atoms. Furthermore, the presence of these vacancies results in various electrical behaviors, categorizing them as semiconductors (V_Mo), metals (V_N3Si), magnetic semiconductors (V_N1), magnetic metals (V_NSi3), and half-metals (V_N2 and V_Si). In terms of substitutional doping, the incorporation of 3d transition metal atoms (TMs) at the silicon (Si) sites of β-MoSi₂N₄ monolayers generally induces magnetic characteristics, with notable exceptions for Sc, Ti, and Zn. The magnetic moments associated with TM impurities from V to Cu are calculated to be 1, 2, 3, 4, 3, 2, and 0.98 μ_B, respectively. Remarkably, the systems doped with V, Mn, and Cu attain 100 % spin polarization and exhibit distinctive half-metallic characteristics. These findings highlight the potential to leverage point defects to modulate the properties of monolayer β-MoSi₂N₄, with implications for developing advanced spintronic devices.

本研究利用第一性原理计算全面考察了点缺陷（空位和取代掺杂）如何影响β-MoSi2N4单层的磁性和电子特性。分析表明，具有空位缺陷VMo或VN3Si的β-MoSi2N4单层具有非磁性，而VN1、VN2、VNSi3和VSi则具有磁性，其磁矩主要来源于附近的原子。此外，这些空位的存在导致各种电学行为，将它们分类为半导体（VMo），金属（VN3Si），磁性半导体（VN1），磁性金属（VNSi3）和半金属（VN2和VSi）。在取代掺杂方面，在β-MoSi2N4单层的硅（Si）位置加入三维过渡金属原子（TMs）通常会诱导磁性，但Sc， Ti和Zn明显例外。计算出从V到Cu的TM杂质的磁矩分别为1、2、3、4、3、2和0.98 μB。值得注意的是，掺杂V、Mn和Cu的体系实现了100%的自旋极化，并表现出明显的半金属特性。这些发现突出了利用点缺陷来调节单层β-MoSi2N4性质的潜力，对开发先进的自旋电子器件具有重要意义。

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引用次数: 0

Investigation of defect states, free volume, and interphase interactions in β-Ga2O3/CNT polymer nanocomposites β-Ga2O3/CNT聚合物纳米复合材料的缺陷态、自由体积和界面相互作用研究

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-20 DOI: 10.1016/j.physe.2025.116450

S.A. Ahmadova , Samir F. Samadov , G.B. Ibragimov , I.I. Vinogradov , A.A. Sidorin , D.M. Mirzayeva , B. Mauyey , S. Sakhabayeva , P. Th Le , Matlab N. Mirzayev

Breakthrough innovations continue in the field of developing and studying new-generation materials with superior optical and mechanical properties. In this research, we investigated the defect characteristics, as well as the modification of the local bonding environment and interphase interactions, in a nanocomposite material formed by incorporating β-Ga₂O₃ and carbon nanotubes (CNTs) into a polyvinylidene fluoride (PVDF) matrix using positron annihilation lifetime spectroscopy (PALS) and Raman spectroscopy. Raman studies show that the D and G bands, which are indicators of the structural quality of carbon nanotubes, exhibit weak additional vibrational modes that can be associated with distortions of the β-Ga₂O₃ lattice and modifications of the local Ga–O coordination environment, rather than with the ideal crystalline structure. The observed peak shifts and intensity changes indicate a transition of the interphase interaction into an amorphous state, accompanied by the formation of internal structural stress and defect centers. With increasing β-Ga₂O₃ concentration in the composite material, the decrease in the ID/IG ratio reveals the formation of chemical bonds that strengthen the oxide layer on the surface of the carbon nanotubes. PALS analysis results clearly demonstrated that the type and size of defects strongly depend on the ratio of Ga₂O₃ to carbon nanotubes in the composite. In pure β-Ga₂O₃ structures, medium-sized vacancy clusters (τ₂ = 369 ps) are present, while in carbon nanotubes (τ₂ = 685 ps), and in the composite samples based on them, the τ₂ component increases up to 853 ps. Analysis based on the two-state trapping model showed that the changes in the τb, kd, and τ₂ – τb parameters indicate the occurrence of porosity and defect clustering processes in the composite structure depending on the CNT and β-Ga₂O₃ ratios. The obtained results suggest that new polymer-based composite materials with highly porous structures can serve as fundamental elements in sensor technology, optoelectronic devices, and radiation-resistant equipment.

在开发和研究具有卓越光学和机械性能的新一代材料领域，突破性创新不断涌现。在这项研究中，我们利用正电子湮灭寿命光谱（PALS）和拉曼光谱研究了在聚偏氟乙烯（PVDF）基体中加入β-Ga2O3和碳纳米管（CNTs）形成的纳米复合材料的缺陷特征，以及局部键合环境和间相相互作用的改变。拉曼研究表明，作为碳纳米管结构质量指标的D带和G带表现出微弱的附加振动模式，这可能与β-Ga2O3晶格的畸变和局部Ga-O配位环境的改变有关，而不是与理想的晶体结构有关。观察到的峰移和强度变化表明相间相互作用转变为非晶态，并伴随着内部结构应力和缺陷中心的形成。随着复合材料中β-Ga2O3浓度的增加，ID/IG比值的降低表明碳纳米管表面形成了化学键，强化了氧化层。PALS分析结果清楚地表明，缺陷的类型和尺寸与复合材料中Ga2O3与碳纳米管的比例密切相关。在纯β-Ga2O3结构中，存在中等空位团簇（τ2 = 369 ps），而在碳纳米管（τ2 = 685 ps）中，基于它们的复合材料样品中，τ2组分增加到853 ps。基于双态俘获模型的分析表明，τb、kd和τ2 - τb参数的变化表明复合材料结构中存在孔隙和缺陷团簇过程，这取决于碳纳米管和β-Ga2O3的比例。研究结果表明，具有高多孔结构的新型聚合物基复合材料可以作为传感器技术、光电器件和抗辐射设备的基础元件。

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引用次数: 0

Spin-dependent transport in long semiconductor heterostructures with Rashba effect: A Green’s function approach 具有Rashba效应的长半导体异质结构中自旋相关输运：格林函数方法

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-18 DOI: 10.1016/j.physe.2025.116451

Luna R.N. Oliveira , Cleber F.N. Marchiori , Carlos Moyses Araujo , Marcos G.E. da Luz

The Rashba effect is a manifestation of spin–orbit coupling in systems with structural inversion asymmetry, resulting in a spin-dependent splitting of energy bands in low-dimensional systems. This gives rise to diverse spin-dependent phenomena in semiconductor heterostructures, offering significant potential for spintronic applications. However, a comprehensive theoretical characterization remains incomplete, since most existing approaches are restricted to relatively small structures. In this work, we combine the well-established eight-band Kane model and envelope-function formalism with a recently developed Green’s function approach. The framework allows to obtain analytical expressions for the spin-dependent coherent transport in semiconductor heterostructures with an arbitrary number

N

of cells exhibiting the Rashba effect. In addition, we propose guidelines for enhancing spin polarization and spin-miniband separation in extended semiconductor heterostructures by tuning structural inversion asymmetry. Furthermore, we find that as a geometric parameter is varied, the spin-splitting dynamics present the quantum avoided-crossing behavior. We finally show that, for suitably designed heterostructures, the polarization bands can exhibit step-like (rectangular-wave) profiles. Although our examples focus on GaAs/In-based systems, the results are expected to hold for other semiconductor materials as well.

Rashba效应是结构反转不对称系统中自旋-轨道耦合的一种表现，导致低维系统中能带的自旋依赖分裂。这在半导体异质结构中产生了不同的自旋依赖现象，为自旋电子的应用提供了巨大的潜力。然而，一个全面的理论表征仍然不完整，因为大多数现有的方法仅限于相对较小的结构。在这项工作中，我们将完善的八波段凯恩模型和包络函数形式主义与最近开发的格林函数方法相结合。该框架允许获得半导体异质结构中具有任意N个显示Rashba效应的细胞的自旋相关相干输运的解析表达式。此外，我们还提出了通过调整结构反转不对称来增强扩展半导体异质结构中自旋极化和自旋微带分离的指导方针。此外，我们发现随着几何参数的变化，自旋分裂动力学表现出量子避交行为。我们最后证明，在适当设计的异质结构下，极化带可以呈现阶梯状（矩形波）轮廓。虽然我们的例子集中在基于GaAs/ in的系统上，但预计结果也适用于其他半导体材料。

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引用次数: 0

Ballistic transport and thermoelectric effect in gated phosphorene superlattices including Fibonacci-type aperiodicity 包含斐波那契型非周期性的门控磷烯超晶格中的弹道输运和热电效应

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-17 DOI: 10.1016/j.physe.2025.116449

E.J. Guzmán , O. Oubram , O. Navarro , I. Rodríguez-Vargas

We theoretically study the thermoelectric effect in phosphorene nano-sheet when the ballistic transport is modulated by gated superlattices. The gating profile consists of electrostatic barriers arranged in periodic and aperiodic Fibonacci-type sequences along the armchair direction of phosphorene. We have calculated the transmission probability and conductance by using the transfer matrix method and Landauer-Büttiker formalism, respectively. We find that the transmission miniband structure of periodic superlattices is greatly fragmented and reduced by introduction of Fibonacci-type aperiodicity. Moreover, the conductance of Fibonacci-type supelattices shows a more pronounced oscillatory trend in contrast to periodic superlattices. Such significant changes in the conductance result in enhanced thermoelectric properties at low temperatures. We find peaks of Seebeck coefficient (

S

) in orders of

0.1 - 0.35

mV/K, with the highest peaks observed in aperiodic superlattices. Also, we obtain high values of figure of merit (

Z T

) in the range of

0.5 - 3

and

2 - 10

for the periodic and aperiodic superlattices, respectively. Furthermore, we find extreme values of

S

(

> 1

mV/K) and

Z T

(

> 10

) at energies very close to the bandgap in both (valence and conduction) bands. By analyzing the ratio of thermal and electronic conductances, we can identify the regions with optimized thermoelectric response. At 300 K, the thermoelectric response is considerably reduced (

Z T \approx 0.12

) due to the thermal contribution of phonons. Our findings indicate that gated phosphorene superlattices could be the basis for high conversion efficiency thermoelectric devices.

从理论上研究了用门控超晶格调制磷烯纳米片的弹道输运时的热电效应。门控轮廓由沿磷烯扶手椅方向按周期性和非周期性斐波那契型顺序排列的静电屏障组成。我们分别用传递矩阵法和landauer - b ttiker公式计算了传输概率和电导。我们发现周期超晶格的传输小带结构在引入斐波那契型非周期后大大破碎和减少。此外，与周期超晶格相比，斐波那契型超晶格的电导表现出更明显的振荡趋势。这种显著的电导变化导致了低温下热电性能的增强。我们发现塞贝克系数(S)的峰值在0.1 ~ 0.35 mV/K数量级，在非周期超晶格中观察到最高峰。此外，我们还获得了周期和非周期超晶格的高品质图（ZT）值，分别在0.5−3和2−10范围内。此外，我们发现S （>1 mV/K）和ZT （>10）在两个（价带和导带）带的能量非常接近带隙的极值。通过分析热导率和电导率的比值，可以确定热电响应最优的区域。在300 K时，由于声子的热贡献，热电响应显著降低（ZT≈0.12）。我们的研究结果表明，门控磷烯超晶格可以成为高转换效率热电器件的基础。

{"title":"Ballistic transport and thermoelectric effect in gated phosphorene superlattices including Fibonacci-type aperiodicity","authors":"E.J. Guzmán , O. Oubram , O. Navarro , I. Rodríguez-Vargas","doi":"10.1016/j.physe.2025.116449","DOIUrl":"10.1016/j.physe.2025.116449","url":null,"abstract":"<div><div>We theoretically study the thermoelectric effect in phosphorene nano-sheet when the ballistic transport is modulated by gated superlattices. The gating profile consists of electrostatic barriers arranged in periodic and aperiodic Fibonacci-type sequences along the armchair direction of phosphorene. We have calculated the transmission probability and conductance by using the transfer matrix method and Landauer-Büttiker formalism, respectively. We find that the transmission miniband structure of periodic superlattices is greatly fragmented and reduced by introduction of Fibonacci-type aperiodicity. Moreover, the conductance of Fibonacci-type supelattices shows a more pronounced oscillatory trend in contrast to periodic superlattices. Such significant changes in the conductance result in enhanced thermoelectric properties at low temperatures. We find peaks of Seebeck coefficient (<span><math><mi>S</mi></math></span>) in orders of <span><math><mrow><mn>0</mn><mo>.</mo><mn>1</mn><mo>−</mo><mn>0</mn><mo>.</mo><mn>35</mn></mrow></math></span> mV/K, with the highest peaks observed in aperiodic superlattices. Also, we obtain high values of figure of merit (<span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span>) in the range of <span><math><mrow><mn>0</mn><mo>.</mo><mn>5</mn><mo>−</mo><mn>3</mn></mrow></math></span> and <span><math><mrow><mn>2</mn><mo>−</mo><mn>10</mn></mrow></math></span> for the periodic and aperiodic superlattices, respectively. Furthermore, we find extreme values of <span><math><mi>S</mi></math></span> (<span><math><mrow><mo>></mo><mn>1</mn></mrow></math></span> mV/K) and <span><math><mrow><mi>Z</mi><mi>T</mi></mrow></math></span> (<span><math><mrow><mo>></mo><mn>10</mn></mrow></math></span>) at energies very close to the bandgap in both (valence and conduction) bands. By analyzing the ratio of thermal and electronic conductances, we can identify the regions with optimized thermoelectric response. At 300 K, the thermoelectric response is considerably reduced (<span><math><mrow><mi>Z</mi><mi>T</mi><mo>≈</mo><mn>0</mn><mo>.</mo><mn>12</mn></mrow></math></span>) due to the thermal contribution of phonons. Our findings indicate that gated phosphorene superlattices could be the basis for high conversion efficiency thermoelectric devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116449"},"PeriodicalIF":2.9,"publicationDate":"2025-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145840163","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Study of linear and nonlinear absorption and refractive index changes in multilayered spherical quantum dots for various excited states 不同激发态下多层球形量子点的线性和非线性吸收及折射率变化研究

IF 2.9 3区物理与天体物理 Q3 NANOSCIENCE & NANOTECHNOLOGY

Physica E-low-dimensional Systems & Nanostructures

Pub Date : 2025-12-17 DOI: 10.1016/j.physe.2025.116445

A. Fakkahi , Frankbelson dos S. Azevedo , H. Azmi , M. Jaouane , J. El-Hamouchi , A. Sali , A. Ed-Dahmouny , K. El-Bakkari , R. Arraoui , A. Mazouz , M. Jaafar

This study investigates the linear and nonlinear optical properties of multilayered spherical quantum dots by focusing on electronic transitions between the

s \to p

,

p \to d

, and

d \to f

states. Using the Finite Element Method (FEM) within the Effective Mass Approximation (EMA), we calculate the linear, third-order nonlinear, and total optical absorption coefficients, as well as the corresponding changes in the refractive index. Our results reveal distinct spectral features associated with each type of transition, highlighting the influence of quantum confinement on the absorption and refractive index behavior. In particular, we find that the nonlinear optical response becomes increasingly significant for higher excited-state transitions, where the third-order nonlinear absorption may surpass the linear contribution in the vicinity of resonance. This behavior is observed across multiple excitation pathways, indicating that the dominance of nonlinear effects may be a general feature associated with transitions involving larger spatial extension of the electronic wavefunctions. The interplay between these transitions governs the overall optical response of the quantum dots, providing insight into their potential applications in optoelectronic and nanophotonic devices. These results suggest that multilayered spherical quantum dots can be engineered to selectively enhance nonlinear optical processes, making them promising candidates for the development of tunable, intensity-dependent photonic components.

本文通过研究s→p、p→d和d→f态之间的电子跃迁，研究了多层球形量子点的线性和非线性光学性质。利用有效质量近似（EMA）中的有限单元法（FEM），我们计算了线性、三阶非线性和全光吸收系数，以及相应的折射率变化。我们的研究结果揭示了与每种跃迁类型相关的不同光谱特征，突出了量子限制对吸收和折射率行为的影响。特别是，我们发现非线性光学响应在高激发态跃迁中变得越来越重要，其中三阶非线性吸收可能超过共振附近的线性贡献。这种行为在多个激发途径中都可以观察到，这表明非线性效应的主导地位可能是与涉及电子波函数更大空间扩展的跃迁相关的一般特征。这些跃迁之间的相互作用决定了量子点的整体光学响应，为其在光电和纳米光子器件中的潜在应用提供了见解。这些结果表明，多层球形量子点可以被设计成选择性地增强非线性光学过程，使它们成为开发可调谐的、强度依赖的光子元件的有希望的候选者。

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引用次数: 0