In this study, we fabricated a broadband terahertz (THz) modulator based on an optically controlled GeSe2/Si heterojunction via magnetron sputtering and vacuum selenization. The structural and morphological properties of the fabricated GeSe2 film were characterized using XRD, Raman, SEM, and AFM. Under 532 nm laser excitation, the device exhibited a modulation depth more seven times higher than that of bare silicon. At a pump density of 1500 mW/cm2, effective modulation was achieved over a broad bandwidth of 0.2–1 THz, with a maximum modulation depth of ∼60 % at 1 THz. Systematic analysis revealed that the enhanced modulation performance originates from efficient separation and accumulation of photogenerated carriers at the heterojunction interface. Therefore, this study not only provides fundamental insights into the optoelectronic dynamics of GeSe2-based heterostructures, but also supports their potential for application in advanced THz devices, including modulators, filters, and polarizers.
{"title":"Optically controlled high-performance terahertz modulator enabled by GeSe2/Si heterojunctions","authors":"Tong Lv , Qifubo Geng , Xunjun He , Mingze Zhang , Sergey Maksimenko","doi":"10.1016/j.physe.2025.116448","DOIUrl":"10.1016/j.physe.2025.116448","url":null,"abstract":"<div><div>In this study, we fabricated a broadband terahertz (THz) modulator based on an optically controlled GeSe<sub>2</sub>/Si heterojunction via magnetron sputtering and vacuum selenization. The structural and morphological properties of the fabricated GeSe2 film were characterized using XRD, Raman, SEM, and AFM. Under 532 nm laser excitation, the device exhibited a modulation depth more seven times higher than that of bare silicon. At a pump density of 1500 mW/cm<sup>2</sup>, effective modulation was achieved over a broad bandwidth of 0.2–1 THz, with a maximum modulation depth of ∼60 % at 1 THz. Systematic analysis revealed that the enhanced modulation performance originates from efficient separation and accumulation of photogenerated carriers at the heterojunction interface. Therefore, this study not only provides fundamental insights into the optoelectronic dynamics of GeSe<sub>2</sub>-based heterostructures, but also supports their potential for application in advanced THz devices, including modulators, filters, and polarizers.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116448"},"PeriodicalIF":2.9,"publicationDate":"2025-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787220","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}
Pub Date : 2025-12-12DOI: 10.1016/j.physe.2025.116443
E.A. Vardanyan , G.A. Mantashian , N. Zeiri , P.A. Mantashyan , S. Thomas , D.B. Hayrapetyan
Boomerang-shaped semiconductor quantum nanostructures, also referred to as nanoboomerangs, offer unique optical and electronic properties due to their asymmetrical geometry, which enhances the spatial separation of charge carriers. This study investigates the influence of external electric fields on the excitonic states, dipole moments, and absorption spectra of these structures. Using the finite element method, we solve the Schrödinger equation to obtain the energy spectra and wave functions, which are then applied in a variational approach to model excitonic properties. The results reveal that the application of an electric field induces significant redshifts in the absorption spectrum due to the Stark effect, alongside variations in oscillator strengths. Strong overlap between wave functions of the same parity results in enhanced transitions, while mixed-parity transitions are amplified by the field-induced redistribution of charge carrier probability densities. The calculated dipole moments demonstrate field-dependent saturation behavior, reaching values as high as 725 Debye, attributable to the unique geometry of the boomerang-shaped nanostructures.
{"title":"Enhanced dipole moment and absorption spectrum in CdSe nanoboomerang under external electric field","authors":"E.A. Vardanyan , G.A. Mantashian , N. Zeiri , P.A. Mantashyan , S. Thomas , D.B. Hayrapetyan","doi":"10.1016/j.physe.2025.116443","DOIUrl":"10.1016/j.physe.2025.116443","url":null,"abstract":"<div><div>Boomerang-shaped semiconductor quantum nanostructures, also referred to as nanoboomerangs, offer unique optical and electronic properties due to their asymmetrical geometry, which enhances the spatial separation of charge carriers. This study investigates the influence of external electric fields on the excitonic states, dipole moments, and absorption spectra of these structures. Using the finite element method, we solve the Schrödinger equation to obtain the energy spectra and wave functions, which are then applied in a variational approach to model excitonic properties. The results reveal that the application of an electric field induces significant redshifts in the absorption spectrum due to the Stark effect, alongside variations in oscillator strengths. Strong overlap between wave functions of the same parity results in enhanced transitions, while mixed-parity transitions are amplified by the field-induced redistribution of charge carrier probability densities. The calculated dipole moments demonstrate field-dependent saturation behavior, reaching values as high as 725 Debye, attributable to the unique geometry of the boomerang-shaped nanostructures.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116443"},"PeriodicalIF":2.9,"publicationDate":"2025-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787202","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}
Pub Date : 2025-12-10DOI: 10.1016/j.physe.2025.116446
A.M. Hassanien
The structural, morphological, and optical spectroscopic properties of hexadecafluoro zinc phthalocyanine (ZnPcF16) are promising investigations that can be useful in optoelectronic applications. The nature of the crystallographic structure and morphology characteristics were explored by field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD) investigations. To determine some crucial optical properties of the ZnPcF16 dye in solution, such as absorption peaks position, photoluminescence emission peaks position, oscillator strengths () and electric dipole strength (), spectrum behavior of the absorbance, fluorescent properties, and molar absorption coefficient spectra of ZnPcF16 in Dimethyl Sulfoxide (DMSO) were examined. Absorbance spectra, transmittance, reflectance, and photoluminescence (PL) of ZnPcF16 thin films before and after annealing at 373 K & 473 K in an air ambient for 2 h were used to deduce the optical band transitions, emission peaks position, and dispersion behaviour. This study demonstrates that the ZnPcF16 organic compound is characterized by good thermal stability, appropriate optical band gap, and dielectric properties, which offer potential uses as an active photonic organic material and should be properly addressed in the device design of optoelectronic technological devices.
{"title":"Optoelectronic applications of hexadecafluoro zinc phthalocyanine (ZnPcF16) thin films: structural, morphological, and optical characteristics","authors":"A.M. Hassanien","doi":"10.1016/j.physe.2025.116446","DOIUrl":"10.1016/j.physe.2025.116446","url":null,"abstract":"<div><div>The structural, morphological, and optical spectroscopic properties of hexadecafluoro zinc phthalocyanine <strong>(ZnPcF16)</strong> are promising investigations that can be useful in optoelectronic applications. The nature of the crystallographic structure and morphology characteristics were explored by field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD) investigations. To determine some crucial optical properties of the <strong>ZnPcF16</strong> dye in solution, such as absorption peaks position, photoluminescence emission peaks position, oscillator strengths (<span><math><mrow><mi>f</mi></mrow></math></span>) and electric dipole strength (<span><math><mrow><msup><mi>q</mi><mn>2</mn></msup></mrow></math></span>), spectrum behavior of the absorbance, fluorescent properties, and molar absorption coefficient spectra of <strong>ZnPcF16</strong> in Dimethyl Sulfoxide (DMSO) were examined. Absorbance spectra, transmittance, reflectance, and photoluminescence (PL) of <strong>ZnPcF16</strong> thin films before and after annealing at 373 K & 473 K in an air ambient for 2 h were used to deduce the optical band transitions, emission peaks position, and dispersion behaviour. This study demonstrates that the <strong>ZnPcF16</strong> organic compound is characterized by good thermal stability, appropriate optical band gap, and dielectric properties, which offer potential uses as an active photonic organic material and should be properly addressed in the device design of optoelectronic technological devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116446"},"PeriodicalIF":2.9,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145787221","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}
Pub Date : 2025-12-10DOI: 10.1016/j.physe.2025.116441
Jiansheng Hu , Yingliang Chen , Zhaoming Fu , Peizhi Yang , Xiaobo Feng
We present a comprehensive theoretical study on the stacking-dependent photoconductivity of bilayer silicene under external electric and exchange fields, with a focus on the critical role of spin-orbit coupling (SOC). Using the Kane-Mele tight-binding model combined with Kubo formalism, we systematically investigate the interband and intraband optical conductivity across infrared to visible spectral ranges for both AA- and AB-stacked configurations. The calculations reveal that the SOC induces distinct bandgap hierarchies (16 meV for AA stacking vs 7.8 meV for AB stacking) and triggers a redshift in infrared photoconductivity, with AB stacking exhibiting stronger SOC sensitivity. AA stacking maintains stable visible-range peaks while AB stacking shows dual peak modulation and far-infrared enhancement above V = 0.15 eV. Exchange fields generate spin-split van Hove singularities, with AB stacking exhibiting accelerated conductivity growth above M = 0.05 eV. The sign reversal of imaginary conductivity at ℏω = 2 eV enables plasmonic mode selection. These findings establish a unified framework for field-controlled optoelectronic response in bilayer silicene, providing design principles for tunable photodetectors and quantum spin devices.
{"title":"Stacking-dependent photoconductivity in bilayer silicene: external-field modulation via spin-orbit coupling","authors":"Jiansheng Hu , Yingliang Chen , Zhaoming Fu , Peizhi Yang , Xiaobo Feng","doi":"10.1016/j.physe.2025.116441","DOIUrl":"10.1016/j.physe.2025.116441","url":null,"abstract":"<div><div>We present a comprehensive theoretical study on the stacking-dependent photoconductivity of bilayer silicene under external electric and exchange fields, with a focus on the critical role of spin-orbit coupling (SOC). Using the Kane-Mele tight-binding model combined with Kubo formalism, we systematically investigate the interband and intraband optical conductivity across infrared to visible spectral ranges for both AA- and AB-stacked configurations. The calculations reveal that the SOC induces distinct bandgap hierarchies (16 meV for AA stacking <em>vs</em> 7.8 meV for AB stacking) and triggers a redshift in infrared photoconductivity, with AB stacking exhibiting stronger SOC sensitivity. AA stacking maintains stable visible-range peaks while AB stacking shows dual peak modulation and far-infrared enhancement above <em>V</em> = 0.15 eV. Exchange fields generate spin-split van Hove singularities, with AB stacking exhibiting accelerated conductivity growth above <em>M</em> = 0.05 eV. The sign reversal of imaginary conductivity at ℏ<em>ω</em> = 2 eV enables plasmonic mode selection. These findings establish a unified framework for field-controlled optoelectronic response in bilayer silicene, providing design principles for tunable photodetectors and quantum spin devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116441"},"PeriodicalIF":2.9,"publicationDate":"2025-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737369","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}
Pub Date : 2025-12-09DOI: 10.1016/j.physe.2025.116444
A.P. Garrido , P.A. Orellana , A. Matos-Abiague
We theoretically investigate the localization properties of Majorana states (MSs) in proximitized, planar Josephson Junctions (JJs) oriented along different crystallographic orientations and in the presence of an in-plane magnetic field and Rashba and Dresselhaus spin–orbit couplings. We show that two types of MSs may emerge when the junction transits into the topological superconducting state. In one case, referred to as end-like MSs, the Majorana quasiparticles are mainly localized inside the normal region at the opposite ends of the junction. In contrast, edge-like MSs extend along the opposite edges of the system, perpendicular to the junction channel. We show how the MSs can transit from end-like to edge-like and vice versa by tuning the magnetic field strength and/or the superconducting phase difference across the junction. In the case of phase-unbiased JJs the transition may occur as the ground state phase difference self-adjusts its value when the Zeeman field is varied. We propose exploiting the extended nature of edge-like MSs as effective interconnects enabling the coupling between topological states in adjacent planar JJs. The impact of electrostatic disorder on the MSs is also analyzed.
{"title":"Majorana edge and end states in planar Josephson junctions","authors":"A.P. Garrido , P.A. Orellana , A. Matos-Abiague","doi":"10.1016/j.physe.2025.116444","DOIUrl":"10.1016/j.physe.2025.116444","url":null,"abstract":"<div><div>We theoretically investigate the localization properties of Majorana states (MSs) in proximitized, planar Josephson Junctions (JJs) oriented along different crystallographic orientations and in the presence of an in-plane magnetic field and Rashba and Dresselhaus spin–orbit couplings. We show that two types of MSs may emerge when the junction transits into the topological superconducting state. In one case, referred to as end-like MSs, the Majorana quasiparticles are mainly localized inside the normal region at the opposite ends of the junction. In contrast, edge-like MSs extend along the opposite edges of the system, perpendicular to the junction channel. We show how the MSs can transit from end-like to edge-like and vice versa by tuning the magnetic field strength and/or the superconducting phase difference across the junction. In the case of phase-unbiased JJs the transition may occur as the ground state phase difference self-adjusts its value when the Zeeman field is varied. We propose exploiting the extended nature of edge-like MSs as effective interconnects enabling the coupling between topological states in adjacent planar JJs. The impact of electrostatic disorder on the MSs is also analyzed.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116444"},"PeriodicalIF":2.9,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737370","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}
Pub Date : 2025-12-04DOI: 10.1016/j.physe.2025.116442
José A.S. Laranjeira , Kleuton A.L. Lima , Nicolas F. Martins , Luiz A. Ribeiro Junior , Douglas S. Galvão , Luis A. Cabral , Julio R. Sambrano
The quest for sustainable and efficient energy storage has driven the exploration of sodium-ion batteries (SIBs) as promising alternatives to lithium-ion systems. However, the larger ionic radius of sodium poses intrinsic challenges such as slow diffusion and structural strain in conventional electrode materials. As a contribution to addressing these limitations, the -Irida-graphene (-IG) is herein introduced, a novel two-dimensional (2D) carbon allotrope derived from Irida-graphene, featuring a diverse polygonal lattice of 3-, 4-, 6-, 8-, and 9-membered carbon rings. Through density functional theory and ab initio molecular dynamics simulations, -IG demonstrated remarkable thermal, dynamical, and mechanical stability, coupled with intrinsic conductive character and efficient sodium-ion mobility (energy barriers eV). Furthermore, the adsorption of sodium ions was energetically favorable, delivering an impressive predicted specific capacity of 554.5 mAh/g. The reported findings highlight -IG as a good potential anode candidate for next-generation SIBs, offering high-rate performance and structural robustness, and expanding the functional design space for advanced carbon-based electrode materials.
{"title":"β-Irida-graphene: A new 2D carbon allotrope for sodium-ion battery anodes","authors":"José A.S. Laranjeira , Kleuton A.L. Lima , Nicolas F. Martins , Luiz A. Ribeiro Junior , Douglas S. Galvão , Luis A. Cabral , Julio R. Sambrano","doi":"10.1016/j.physe.2025.116442","DOIUrl":"10.1016/j.physe.2025.116442","url":null,"abstract":"<div><div>The quest for sustainable and efficient energy storage has driven the exploration of sodium-ion batteries (SIBs) as promising alternatives to lithium-ion systems. However, the larger ionic radius of sodium poses intrinsic challenges such as slow diffusion and structural strain in conventional electrode materials. As a contribution to addressing these limitations, the <span><math><mi>β</mi></math></span>-Irida-graphene (<span><math><mi>β</mi></math></span>-IG) is herein introduced, a novel two-dimensional (2D) carbon allotrope derived from Irida-graphene, featuring a diverse polygonal lattice of 3-, 4-, 6-, 8-, and 9-membered carbon rings. Through density functional theory and <em>ab initio</em> molecular dynamics simulations, <span><math><mi>β</mi></math></span>-IG demonstrated remarkable thermal, dynamical, and mechanical stability, coupled with intrinsic conductive character and efficient sodium-ion mobility (energy barriers <span><math><mrow><mo><</mo><mn>0</mn><mo>.</mo><mn>30</mn></mrow></math></span> eV). Furthermore, the adsorption of sodium ions was energetically favorable, delivering an impressive predicted specific capacity of 554.5 mAh/g. The reported findings highlight <span><math><mi>β</mi></math></span>-IG as a good potential anode candidate for next-generation SIBs, offering high-rate performance and structural robustness, and expanding the functional design space for advanced carbon-based electrode materials.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116442"},"PeriodicalIF":2.9,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737371","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}
Pub Date : 2025-12-04DOI: 10.1016/j.physe.2025.116435
Anjali Bhattacharyya, Madhusudhana Rao N, Basit Iqbal, Purnendu Ray
Research into Diluted Magnetic Semiconductors (DMS) has experienced significant advancement over the past decade. This progress is largely attributable to the development of sophisticated synthesis techniques, which have enabled the fabrication of high-quality samples with well-characterized properties for experimental study. Consequently, DMS are widely regarded as a leading material platform for the development of spintronic devices. This study comprehensively investigates the first-principles study of SnS2 and structural, morphological, chemical, optical, and magnetic properties of hydrothermally prepared pure and Cobalt-doped SnS2 (1 %, 3 %, 5 %, 7 %) nanoparticles. X-ray diffraction analysis confirms the preservation of the hexagonal crystal phase post-doping. In contrast, Williamson-Hall (W-H) plot analysis indicates an increase in crystallite size from 32.9 nm to 66.8 nm with Co concentration. FESEM reveals a nanoflower-like morphology. X-ray photoelectron spectroscopy verifies the presence of Sn4+ and S2− states and confirms the successful incorporation of Co dopants, which exhibit mixed Co2+/Co3+ oxidation states. Optical characterization demonstrates a reduction in reflectance and a narrowing of the optical band gap from 2.26 eV to 1.56 eV with doping. Density functional theory shows that the band gap of pure SnS2 is direct. The Urbach energy, initially increasing up to 3 % Co doping, suggests a rise in structural disorder, followed by a subsequent decrease. A reduction in the refractive index from 4.62 to 3.10 indicates enhanced optical transmission, while a increase in optical and decrease in electrical conductivity is observed. The tunability of the emission wavelength across the visible spectrum, as observed in the photoluminescence (PL) spectra, is directly enabled by Co-doping. This controllability underscores the material's strong potential for application in advanced optoelectronic devices. Furthermore, the observed hysteresis loop confirms the emergence of ferromagnetic ordering upon cobalt doping. These findings collectively demonstrate that Cobalt-doped SnS2 is a promising diluted magnetic semiconductor (DMS) material, whose tunable properties make it a strong candidate for application in spintronics and multifunctional optoelectronic devices.
{"title":"Cobalt-induced Multifunctionality: Ferromagnetism and tunable optoelectronic properties in hydrothermally synthesized SnS2 nanoparticles","authors":"Anjali Bhattacharyya, Madhusudhana Rao N, Basit Iqbal, Purnendu Ray","doi":"10.1016/j.physe.2025.116435","DOIUrl":"10.1016/j.physe.2025.116435","url":null,"abstract":"<div><div>Research into Diluted Magnetic Semiconductors (DMS) has experienced significant advancement over the past decade. This progress is largely attributable to the development of sophisticated synthesis techniques, which have enabled the fabrication of high-quality samples with well-characterized properties for experimental study. Consequently, DMS are widely regarded as a leading material platform for the development of spintronic devices. This study comprehensively investigates the first-principles study of SnS<sub>2</sub> and structural, morphological, chemical, optical, and magnetic properties of hydrothermally prepared pure and Cobalt-doped SnS<sub>2</sub> (1 %, 3 %, 5 %, 7 %) nanoparticles. X-ray diffraction analysis confirms the preservation of the hexagonal crystal phase post-doping. In contrast, Williamson-Hall (W-H) plot analysis indicates an increase in crystallite size from 32.9 nm to 66.8 nm with Co concentration. FESEM reveals a nanoflower-like morphology. X-ray photoelectron spectroscopy verifies the presence of Sn<sup>4+</sup> and S<sup>2−</sup> states and confirms the successful incorporation of Co dopants, which exhibit mixed Co<sup>2+</sup>/Co<sup>3+</sup> oxidation states. Optical characterization demonstrates a reduction in reflectance and a narrowing of the optical band gap from 2.26 eV to 1.56 eV with doping. Density functional theory shows that the band gap of pure SnS<sub>2</sub> is direct. The Urbach energy, initially increasing up to 3 % Co doping, suggests a rise in structural disorder, followed by a subsequent decrease. A reduction in the refractive index from 4.62 to 3.10 indicates enhanced optical transmission, while a increase in optical and decrease in electrical conductivity is observed. The tunability of the emission wavelength across the visible spectrum, as observed in the photoluminescence (PL) spectra, is directly enabled by Co-doping. This controllability underscores the material's strong potential for application in advanced optoelectronic devices. Furthermore, the observed hysteresis loop confirms the emergence of ferromagnetic ordering upon cobalt doping. These findings collectively demonstrate that Cobalt-doped SnS<sub>2</sub> is a promising diluted magnetic semiconductor (DMS) material, whose tunable properties make it a strong candidate for application in spintronics and multifunctional optoelectronic devices.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116435"},"PeriodicalIF":2.9,"publicationDate":"2025-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737372","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}
Pub Date : 2025-12-03DOI: 10.1016/j.physe.2025.116440
Mohammad Hossein Gholamyan , Hamed Jafarzadeh , Seyed Ebrahim Hosseini
In this manuscript, we investigate the electronic and optical properties of four graphyne nanoribbons containing square rings and compare them with those of graphene. Some bonds in the graphyne structures exhibit acetylene characteristics, and the nanoribbons appear in two edge configurations: armchair and zigzag. The calculations were performed using Density Functional Theory (DFT). Unlike graphene, certain graphyne configurations show a significant energy gap in the zigzag form, with some structures exhibiting a gap even larger than that of graphene. The range of realistic and homogeneous dielectric responses is also broader in some graphyne nanoribbons, leading to improved optical performance. The diverse properties observed in these systems suggest that graphyne nanoribbons may serve as promising candidates for future electronic and optical applications, such as transistors and sensors.
{"title":"First-principles study of the electronic and optical properties of square-ring graphyne nanoribbons","authors":"Mohammad Hossein Gholamyan , Hamed Jafarzadeh , Seyed Ebrahim Hosseini","doi":"10.1016/j.physe.2025.116440","DOIUrl":"10.1016/j.physe.2025.116440","url":null,"abstract":"<div><div>In this manuscript, we investigate the electronic and optical properties of four graphyne nanoribbons containing square rings and compare them with those of graphene. Some bonds in the graphyne structures exhibit acetylene characteristics, and the nanoribbons appear in two edge configurations: armchair and zigzag. The calculations were performed using Density Functional Theory (DFT). Unlike graphene, certain graphyne configurations show a significant energy gap in the zigzag form, with some structures exhibiting a gap even larger than that of graphene. The range of realistic and homogeneous dielectric responses is also broader in some graphyne nanoribbons, leading to improved optical performance. The diverse properties observed in these systems suggest that graphyne nanoribbons may serve as promising candidates for future electronic and optical applications, such as transistors and sensors.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116440"},"PeriodicalIF":2.9,"publicationDate":"2025-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737373","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}
Pub Date : 2025-12-02DOI: 10.1016/j.physe.2025.116439
Yikang Liu , Songbo Xiong , Zejiang Peng , Qiuming Liu , Mengqiu Long , Tong Chen
Two-dimensional transition metal-sulfur compound-derived materials have emerged as a significant research focus in the fields of condensed matter physics and optoelectronics, owing to their outstanding electronic, optical, thermal, and mechanical properties. In this study, we systematically investigate the electronic structures, density of states, optical properties, and optoelectronic performances of five 2D transition metal-sulfur compounds and their hydrogenation-derived monolayers, including MoS2, MoSe2, MoSSe, MoSH, and MoSeH, based on first-principles calculations. The results reveal that, under strain-free conditions, monolayer MoS2 and MoSe2 exhibit direct bandgap semiconductor characteristics with bandgap values of 1.75 eV and 1.53 eV, respectively. In contrast, the Janus MoSSe monolayer breaks the out-of-plane symmetry, resulting in the formation of an indirect bandgap of 1.21 eV, and its electronic properties undergo a semiconductor-to-metal transition under a compressive strain of 6 %. The hydrogenated derivatives MoSH and MoSeH display metallic behavior. The intrinsic MoS2, MoSe2, and MoSSe monolayers demonstrate excellent optical absorption characteristics under strain engineering. Based on these materials, p–i–n junction devices were further constructed, showing that MoS2 and MoSe2 possess strong absorption coefficients in the visible-light region, with peak values of 1.40 × 107 cm−1 and 1.14 × 107 cm−1, respectively. In comparison, MoSSe exhibits a pronounced absorption peak in the infrared region, reaching 1.59 × 107 cm−1, along with a remarkably high photoconductivity, making it a promising candidate for high-performance infrared photodetectors. Overall, this study provides a potential pathway toward the development of advanced optoelectronic devices based on these two-dimensional materials.
{"title":"Strain-tunable electronic and optoelectronic properties of 2D MoS2 and its derivatives: A DFT study","authors":"Yikang Liu , Songbo Xiong , Zejiang Peng , Qiuming Liu , Mengqiu Long , Tong Chen","doi":"10.1016/j.physe.2025.116439","DOIUrl":"10.1016/j.physe.2025.116439","url":null,"abstract":"<div><div>Two-dimensional transition metal-sulfur compound-derived materials have emerged as a significant research focus in the fields of condensed matter physics and optoelectronics, owing to their outstanding electronic, optical, thermal, and mechanical properties. In this study, we systematically investigate the electronic structures, density of states, optical properties, and optoelectronic performances of five 2D transition metal-sulfur compounds and their hydrogenation-derived monolayers, including MoS<sub>2</sub>, MoSe<sub>2</sub>, MoSSe, MoSH, and MoSeH, based on first-principles calculations. The results reveal that, under strain-free conditions, monolayer MoS<sub>2</sub> and MoSe<sub>2</sub> exhibit direct bandgap semiconductor characteristics with bandgap values of 1.75 eV and 1.53 eV, respectively. In contrast, the Janus MoSSe monolayer breaks the out-of-plane symmetry, resulting in the formation of an indirect bandgap of 1.21 eV, and its electronic properties undergo a semiconductor-to-metal transition under a compressive strain of 6 %. The hydrogenated derivatives MoSH and MoSeH display metallic behavior. The intrinsic MoS<sub>2</sub>, MoSe<sub>2</sub>, and MoSSe monolayers demonstrate excellent optical absorption characteristics under strain engineering. Based on these materials, p–i–n junction devices were further constructed, showing that MoS<sub>2</sub> and MoSe<sub>2</sub> possess strong absorption coefficients in the visible-light region, with peak values of 1.40 × 10<sup>7</sup> cm<sup>−1</sup> and 1.14 × 10<sup>7</sup> cm<sup>−1</sup>, respectively. In comparison, MoSSe exhibits a pronounced absorption peak in the infrared region, reaching 1.59 × 10<sup>7</sup> cm<sup>−1</sup>, along with a remarkably high photoconductivity, making it a promising candidate for high-performance infrared photodetectors. Overall, this study provides a potential pathway toward the development of advanced optoelectronic devices based on these two-dimensional materials.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116439"},"PeriodicalIF":2.9,"publicationDate":"2025-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682473","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}
Pub Date : 2025-12-01DOI: 10.1016/j.physe.2025.116438
Doan M. Quang , Nguyen Q. Bau , Le T.T. Phuong , Bui D. Hoi
We investigate the thermoelectric transport properties of gapped tilted-8- borophene, a two-dimensional boron allotrope with anisotropic electronic dispersion, using the semiclassical Boltzmann transport theory within the constant relaxation time approximation. The low-energy effective Hamiltonian incorporates a tilted Dirac cone structure with an induced bandgap, tunable via strain or substrate interactions. We calculate the electrical conductivity, Seebeck coefficient, and thermopower as functions of chemical potential, energy gap, and thermal energy. Our results reveal pronounced transport anisotropy in the - and -directions, with the -direction exhibiting higher conductivity and thermopower. Increasing the bandgap enhances the Seebeck coefficient and thermopower by aligning the Fermi level with the band edges, while higher temperatures boost conductivity at the expense of the Seebeck coefficient. These findings highlight the potential of gapped 8- borophene for nanoscale thermoelectric applications.
{"title":"Tunable thermopower in gapped 8-Pmmn borophene","authors":"Doan M. Quang , Nguyen Q. Bau , Le T.T. Phuong , Bui D. Hoi","doi":"10.1016/j.physe.2025.116438","DOIUrl":"10.1016/j.physe.2025.116438","url":null,"abstract":"<div><div>We investigate the thermoelectric transport properties of gapped tilted-8-<span><math><mrow><mi>P</mi><mi>m</mi><mi>m</mi><mi>n</mi></mrow></math></span> borophene, a two-dimensional boron allotrope with anisotropic electronic dispersion, using the semiclassical Boltzmann transport theory within the constant relaxation time approximation. The low-energy effective Hamiltonian incorporates a tilted Dirac cone structure with an induced bandgap, tunable via strain or substrate interactions. We calculate the electrical conductivity, Seebeck coefficient, and thermopower as functions of chemical potential, energy gap, and thermal energy. Our results reveal pronounced transport anisotropy in the <span><math><mi>x</mi></math></span>- and <span><math><mi>y</mi></math></span>-directions, with the <span><math><mi>x</mi></math></span>-direction exhibiting higher conductivity and thermopower. Increasing the bandgap enhances the Seebeck coefficient and thermopower by aligning the Fermi level with the band edges, while higher temperatures boost conductivity at the expense of the Seebeck coefficient. These findings highlight the potential of gapped 8-<span><math><mrow><mi>P</mi><mi>m</mi><mi>m</mi><mi>n</mi></mrow></math></span> borophene for nanoscale thermoelectric applications.</div></div>","PeriodicalId":20181,"journal":{"name":"Physica E-low-dimensional Systems & Nanostructures","volume":"177 ","pages":"Article 116438"},"PeriodicalIF":2.9,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145682472","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}
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