Physica E-low-dimensional Systems & Nanostructures最新文献

The key role of anti-solvent temperature in quantum dot/perovskite core-shell nanowire array solar cells 量子点/过氧化物核壳纳米线阵列太阳能电池中反溶剂温度的关键作用

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-12 DOI: 10.1016/j.physe.2024.116131

{"title":"The key role of anti-solvent temperature in quantum dot/perovskite core-shell nanowire array solar cells","authors":"","doi":"10.1016/j.physe.2024.116131","DOIUrl":"10.1016/j.physe.2024.116131","url":null,"abstract":"<div><div>Combining perovskite with infrared quantum dots to construct a core-shell nanostructure nanowire array solar cell can increase the light absorption range and enhance the light absorption and carrier transport efficiency of the solar cell. However, the preparation of a perovskite absorber layer on a nanowire array with quantum dots often presents issues such as high roughness and a large number of lattice defects, which have a negative impact on the photovoltaic performance. The anti-solvent method is a commonly used technique to improve the quality of perovskite. The temperature variation of the anti-solvent can change solubility, and influence the reaction rate and crystal formation process of perovskite, thus affecting its photovoltaic performance. In this study, the quality of perovskite in the core-shell nanostructure nanowire array was improved by controlling the temperature of the anti-solvent (toluene). Experimental results show that as the temperature of toluene increases, the photovoltaic performance is gradually improved. When the toluene temperature was maintained at 75 °C, the device exhibited significantly improved photovoltaic performance with an efficiency of 12.64 %, surpassing the efficiency obtained without any anti-solvent modification. As the temperature of the anti-solvent increases, the absorption of visible and near-infrared light spectrum by the nanowire arrays is enhanced, which promotes the efficient generation of photo-generated carriers. Furthermore, defects in the nanowire arrays gradually decrease, leading to a reduction in carrier recombination. These findings provide valuable insights for advancing core-shell nanostructure nanowire array solar cells.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142446081","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

Design of spintronic devices based on adjustable half-metallicity induced by electric field in A-type antiferromagnetic bilayer NiI2 基于 A 型反铁磁双层 NiI2 中电场诱导的可调半金属性设计自旋电子器件

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-10 DOI: 10.1016/j.physe.2024.116129

{"title":"Design of spintronic devices based on adjustable half-metallicity induced by electric field in A-type antiferromagnetic bilayer NiI2","authors":"","doi":"10.1016/j.physe.2024.116129","DOIUrl":"10.1016/j.physe.2024.116129","url":null,"abstract":"<div><div>Exploring the attainment of half-metallic behavior in two-dimensional (2D) materials through external perturbations is a popular area of current research. In this work, we demonstrate, using first-principles calculations, that bilayer NiI<sub>2</sub> (bi-NiI<sub>2</sub>) is an A-type antiferromagnetic (AFM) semiconductor with an indirect bandgap of 0.86 eV, with the most stable configuration being the AB stacking mode. Upon the application of a vertical electric field, the material transforms from its original semiconducting state into a half-metallic state. Moreover, the spin polarization reverses its orientation whenever the direction of the electric field is altered. This intriguing behavior has inspired us to design a spintronic device based on the A-type AFM bi-NiI<sub>2</sub>. By employing nonequilibrium Green's function (NEGF) combined with density functional theory (DFT) calculations, we find that the device achieves ON/OFF switching by applying vertical electric fields in parallel or anti-parallel configurations in the two leads. The device displays 100 % spin polarization in the parallel configuration (PC) scenario, driven by bias voltage or temperature differences. Utilizing either the parallel or antiparallel configuration (APC) for ON/OFF switching enables the device to exhibit tunneling magnetoresistance (TMR) of up to 1.45 × 10<sup>10</sup> % due to bias voltage and up to 10<sup>11</sup> % thermal TMR arising from temperature differences between the leads. These findings highlight the potential of NiI<sub>2</sub> and A-type AFM bilayers in the design of spintronic devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433333","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

A metasurface for linear-to-circular polarization conversion and sensing based on quasi-BIC 基于准 BIC 的线-圆偏振转换和传感元表面

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-10 DOI: 10.1016/j.physe.2024.116128

{"title":"A metasurface for linear-to-circular polarization conversion and sensing based on quasi-BIC","authors":"","doi":"10.1016/j.physe.2024.116128","DOIUrl":"10.1016/j.physe.2024.116128","url":null,"abstract":"<div><div>This work presents a multifunctional metastructure (MS) which realizes linear to circular polarization conversion and sensing function based on quasi-bound states in the continuum (quasi-BIC). MS is made of silicon dioxide as substrate, and silicon as surface material, by etching cross holes and square holes on it to form a 2×2 structure, through the transmission of terahertz (THz) band, to form an ultrahigh quality factor (<em>Q</em>-factor), and realize the conversion of linearly polarized waves to circularly polarized ones. At 178.190 THz, it achieves a <em>Q</em> value of 2969, and in the range 178.193 TH to 178.200 THz, the axial ratio (AR) is less than 3 dB and the insertion loss is less than 0.0001. In addition, by changing the permittivity of the surrounding environment, the minimum of the output wave will produce a good linear frequency shift. Using this feature, the given device can also be used as a dielectric constant sensor to detect air quality. The device has a sensing sensitivity (<em>S</em>) of 6.415 THz RIU<sup>−1</sup> and a figure of merit (<em>FOM</em>) of 106.9. The parameters (<em>H</em>, <em>w</em><sub>2</sub>, <em>L</em><sub>2</sub>, <em>g</em><sub>2</sub>), incidence angle (<em>θ</em>) and the polarization angle (<em>φ</em>) are discussed. The effects of different parameters on the <em>Q</em>-factor and AR were analyzed, which helped to select the optimal parameters. The design can also be used in communication and biosensing.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425336","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

Resonant tunneling properties of laser dressed hyperbolic Pöschl-Teller double barrier potential 激光穿透双曲波氏-泰勒双势垒的共振隧道特性

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-09 DOI: 10.1016/j.physe.2024.116126

{"title":"Resonant tunneling properties of laser dressed hyperbolic Pöschl-Teller double barrier potential","authors":"","doi":"10.1016/j.physe.2024.116126","DOIUrl":"10.1016/j.physe.2024.116126","url":null,"abstract":"<div><div>We examine the resonant tunneling properties of the laser-dressed hyperbolic Pöschl-Teller double quantum barrier structure. We use the non-equilibrium Green's function method to investigate structure parameters and electric field bias on the transmission properties of the system. The transmission probabilities and resonance energy levels are significantly influenced by the well widths and barrier heights. The barrier height increases, resonance energy levels shift toward higher values, and the resonance peak width narrows, leading to sharper and more selective tunneling behavior. Our results show that increasing the electric field bias leads to a decrease in the transmission probability at the first resonance peak, but this effect is not as strong for the subsequent peaks. Moreover, we find that changes in the laser field's parameter and structure parameters allow for fine control over the electronic spectra, allowing for modifications like red or blue shifts based on particular needs. The significance of comprehending the interaction among structural factors, external fields, and transmission qualities in quantum barrier structures is highlighted by our research, providing valuable information for the development and enhancement of electronic and optoelectronic systems with customized functionality. Our findings show the laser field has a considerable impact on resonant tunneling properties, opening the door to new device applications.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425333","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

Neutral donors confined in semiconductor coupled quantum dot-rings: Position-dependent properties and optical transparency phenomenon 限制在半导体耦合量子点环中的中性供体：位置相关特性和光学透明现象

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-09 DOI: 10.1016/j.physe.2024.116122

{"title":"Neutral donors confined in semiconductor coupled quantum dot-rings: Position-dependent properties and optical transparency phenomenon","authors":"","doi":"10.1016/j.physe.2024.116122","DOIUrl":"10.1016/j.physe.2024.116122","url":null,"abstract":"<div><div>Electronic properties of a neutral donor confined in a <span><math><mi>GaAs</mi></math></span> coupled quantum dot-ring covered by a <span><math><mrow><msub><mrow><mi>Al</mi></mrow><mrow><mn>0</mn><mo>.</mo><mn>3</mn></mrow></msub><msub><mrow><mi>Ga</mi></mrow><mrow><mn>0</mn><mo>.</mo><mn>7</mn></mrow></msub><mi>As</mi></mrow></math></span> matrix were calculated using the finite element method under the effective mass and the envelope function approximations. The proposed model is set up to fit a realistic coupled quantum dot-ring geometry revealed by atomic force microscopy images. The results show that the energy levels and the transition energies in the presence of an electric field strongly depend on the donor center’s angular position. Furthermore, the total optical absorption coefficient is calculated within the two-level approximation and the matrix density formalism. The absorption spectrum shows that the system can be tuned between 5 and <span><math><mrow><mn>30</mn><mspace></mspace><mi>meV</mi></mrow></math></span>. Also, an optical transparency effect for different configurations characterized by specific donor center’s angular positions and electric field values is seen. Finally, a novel redshift is observed when the sample temperature increases.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Correlation of Valence electron structure and properties of monolayer graphene and MX2 (M=Mo, W; X=S, Se, Te): Empirical Electron Theory (EET) investigation 单层石墨烯和 MX2（M=Mo、W；X=S、Se、Te）的价电子结构和性质的相关性：经验电子理论 (EET) 研究

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-08 DOI: 10.1016/j.physe.2024.116124

{"title":"Correlation of Valence electron structure and properties of monolayer graphene and MX2 (M=Mo, W; X=S, Se, Te): Empirical Electron Theory (EET) investigation","authors":"","doi":"10.1016/j.physe.2024.116124","DOIUrl":"10.1016/j.physe.2024.116124","url":null,"abstract":"<div><div>The atomically thin layers of transition-metal dichalcogenide (TMDC) materials have garnered considerable attention due to their exceptional electrical, optical, mechanical, and thermal properties. Hence, it is important to investigate the mechanism of their excellent properties. In this paper, the study is focused on the correlation between valence electron structures (VESs) and mechanical as well as thermal properties of graphene and MX<sub>2</sub> (M = Mo, W; X = S, Se, Te) for revealing their essential mechanisms of properties with an empirical electron theory (EET). A model of Young's modulus is built for the monolayer graphene and MX<sub>2</sub> (M = Mo, W; X = S, Se, Te) based on the VES, which has been verified by the observed ones of elements in the 4th to 6th periods in the periodic table of elements. The calculated bond lengths and mechanical and thermal properties of graphene and MX<sub>2</sub> are in good agreement with experimental ones. The study reveals that the thermal and mechanical properties of MX<sub>2</sub> strongly depend on their valence electron structures. It shows that the melting point, cohesive energy, thermal conductivity, and Young's modulus are modulated by covalence electron pair <em>n</em><sub><em>A</em></sub>, the averaged covalence electron per atom <em>n</em><sub><em>c</em></sub>/atom, covalence electron pair <em>n</em><sub><em>A</em></sub> and linear density of covalent electron on the strongest bond <em>ρ</em><sub><em>l</em></sub>, respectively. The study helps explain the thermal and mechanical properties of two-dimensional (2D) materials and also supplies a reference for their design with high performance by modulating their valence electron structures.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425335","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

Superconductivity and spin density wave in AA stacked bilayer graphene AA 叠层双层石墨烯的超导性和自旋密度波

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-04 DOI: 10.1016/j.physe.2024.116118

引用次数: 0

Generation of femtosecond spin-polarized current pulses at Fe/MgO interface by quasi-static voltage 利用准静态电压在铁/氧化镁界面上产生飞秒自旋极化电流脉冲

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-03 DOI: 10.1016/j.physe.2024.116120

{"title":"Generation of femtosecond spin-polarized current pulses at Fe/MgO interface by quasi-static voltage","authors":"","doi":"10.1016/j.physe.2024.116120","DOIUrl":"10.1016/j.physe.2024.116120","url":null,"abstract":"<div><div>The generation of short spin-current pulses is essential for fast spintronic devices. So far, spin current pulses are generated by femtosecond laser pulses which drive spins from a ferromagnetic metal layer. However, the need for miniaturization, simplicity and energy efficiency favour electric-field control of spintronic devices over optic or thermal control. Here, we combine ab initio calculations of electronic density of states at MgO/Fe interface with continuous model for charge transport to investigate the dynamics of the spin-dependent potential. We demonstrate that the voltage-driven instability of the electronic band structure due to the electronic resonant states at the Fe/MgO interface results in the generation of the femtosecond spin-polarized current pulse with the spin polarization up to <span><math><mrow><mi>P</mi><mo>=</mo><mn>7</mn></mrow></math></span> 00 % that propagates from the interface to the bulk. The dynamics of the current pulses driven by the Stoner instability depends neither on the dielectric relaxation time nor on the details of how the instability is achieved by changing the voltage, i.e. as long as the voltage changes are slow (quasi-static) with respect to the time determined by the spin diffusion constant, being of the order of fs. The presence of the instability can be detected by THz time-domain spectroscopy or pump-probe techniques.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermoelectric properties of MoS2-MoTe2 and MoS2-MoSe2lateral hetero-structures: The effects of external magnetic, transverse electric fields and nanoribbon width MoS2-MoTe2 和 MoS2-MoSe2 侧异质结构的热电性能：外磁场、横向电场和纳米带宽度的影响

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-02 DOI: 10.1016/j.physe.2024.116119

{"title":"Thermoelectric properties of MoS2-MoTe2 and MoS2-MoSe2lateral hetero-structures: The effects of external magnetic, transverse electric fields and nanoribbon width","authors":"","doi":"10.1016/j.physe.2024.116119","DOIUrl":"10.1016/j.physe.2024.116119","url":null,"abstract":"<div><div>Extensive research is underway to improve the thermoelectric properties of materials by enhancing the figure of merit (ZT). In this study, we are investigating the thermoelectric properties of MoS<sub>2</sub>/MoTe<sub>2</sub> and MoS<sub>2</sub>/MoSe<sub>2</sub> lateral heterostructures (LH-S) under the influence of external magnetic fields (EMF) and transverse electric fields (TEF). We employ the non-equilibrium Green's function (N-EGF) and tight-binding (TB) methods for our analysis. The results obtained indicate that the ZT for MoS<sub>2</sub>-MoTe<sub>2</sub> and MoS<sub>2</sub>-MoSe<sub>2</sub> LH-S enhanced with an increase in the TEF. The ZT of MoS<sub>2</sub>-MoSe<sub>2</sub> LH-S increases near room temperature, while the ZT of MoS<sub>2</sub>-MoTe<sub>2</sub> LH-S increases with an increase in EMF across the entire temperature range. Additionally, the ZT for MoS<sub>2</sub>-MoSe<sub>2</sub> LH-S increases with an increase in the nanoribbon width, whereas for MoS<sub>2</sub>-MoTe<sub>2</sub> LH-S, it decreases. The results reveal that the semiconductor type of MoS<sub>2</sub>-MoSe<sub>2</sub> and MoS<sub>2</sub>-MoTe<sub>2</sub> LH-S changes from n-type to p-type when subjected to EMF and transverse TEF. The examination of the temperature dependence of ZT in the presence of TEF and EMF for MoS<sub>2</sub>-MoTe<sub>2</sub> and MoS<sub>2</sub>-MoSe<sub>2</sub> LH-S indicates that these structures are highly promising candidates for use in electrical devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":null,"pages":null},"PeriodicalIF":2.9,"publicationDate":"2024-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142425343","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

Transport through a monolayer-tube junction: Sheet-to-tube spin current 通过单层管交界处的传输：片管自旋电流

IF 2.9 3区物理与天体物理

Physica E-low-dimensional Systems & Nanostructures Pub Date : 2024-10-01 DOI: 10.1016/j.physe.2024.116111

引用次数: 0