Pub Date : 2025-02-28DOI: 10.1016/j.physb.2025.417095
N. Abhiram , Bagavathy Shunmughananthan , Ajay Kesavan , Mohammed Mujahid Alam , Abdullah G. Al-Sehemi , Thangaraju Dheivasigamani
The primary issue related to industrialization is that environmental pollution contributes to human health hazards. One significant cause of environmental contamination is the usage of various dyes in industries. In this context, photocatalysis plays a significant role due to its inherent nature. The cost-effective gel matrix method synthesized two distinct phases of calcium vanadate. The prepared vanadates' phase formation, crystallinity, optical properties and elemental composition were investigated using X-ray Diffraction (XRD), Raman spectroscopy, UV–visible spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The band gap calculation was done from the Tauc plot using the UV absorbance studies. The morphology of the synthesized vanadates was examined using Scanning Electron Microscopy (SEM). Employing methylene blue (MB) as a model dye, the dye degradation illustrated the photocatalytic activity of synthesized semiconductor photocatalyst by irradiating visible light. The degradation efficiency of Ca2V2O7 is 97 % within 4 h, which can be used for removing the dyes from the waste waters.
{"title":"Comprehensive analysis of structural, optical, and photocatalytic properties of single-phase calcium vanadates: Insights into CaV2O6 and Ca2V2O7","authors":"N. Abhiram , Bagavathy Shunmughananthan , Ajay Kesavan , Mohammed Mujahid Alam , Abdullah G. Al-Sehemi , Thangaraju Dheivasigamani","doi":"10.1016/j.physb.2025.417095","DOIUrl":"10.1016/j.physb.2025.417095","url":null,"abstract":"<div><div>The primary issue related to industrialization is that environmental pollution contributes to human health hazards. One significant cause of environmental contamination is the usage of various dyes in industries. In this context, photocatalysis plays a significant role due to its inherent nature. The cost-effective gel matrix method synthesized two distinct phases of calcium vanadate. The prepared vanadates' phase formation, crystallinity, optical properties and elemental composition were investigated using X-ray Diffraction (XRD), Raman spectroscopy, UV–visible spectroscopy and X-ray Photoelectron Spectroscopy (XPS). The band gap calculation was done from the Tauc plot using the UV absorbance studies. The morphology of the synthesized vanadates was examined using Scanning Electron Microscopy (SEM). Employing methylene blue (MB) as a model dye, the dye degradation illustrated the photocatalytic activity of synthesized semiconductor photocatalyst by irradiating visible light. The degradation efficiency of Ca<sub>2</sub>V<sub>2</sub>O<sub>7</sub> is 97 % within 4 h, which can be used for removing the dyes from the waste waters.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417095"},"PeriodicalIF":2.8,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549592","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 : 2025-02-27DOI: 10.1016/j.physb.2025.417091
R. Biswas , S. Mukhopadhyay , C. Sinha
We investigated theoretically the transmission properties of Dirac Fermions tunneling through a periodically (sinusoidal and rectangular) driven electrostatic barrier in Monolayer graphene. For the time harmonic potential with moderate to high the central Floquet band is found to be almost cloaked for the Klein transmitted electron in contrast to electron at higher grazing incidences. As a time periodic drive, we mainly focused on the use of rectangular wave electric signal to modulate the transparency of the barrier. It is noted that the asymmetric Fano resonance, a characteristic feature of photon assisted tunneling, is more likely to occur for rectangular drive in contrast to the harmonic one. The height of the modulating potential is particularly responsible for the dressing effect of the barrier. The position and nature of the FR can be tailored by changing the height and frequency of the rectangular drive. Moreover, the duty cycle of the driving potential turns out to be an important controlling parameter for the transmission process. Thus, the rectangular modulation plays an important role for the occurrence and detection of the Fano resonances which is vital for the use of graphene nanostructure in the field of detectors, sensors, modulators etc. The present work attempts for the first time, to realize the effect of duty cycle on the quantum interference in semiconductor nanostructures.
{"title":"Tunneling of Dirac fermions in graphene nanostructure modulated by time dependent rectangular wave potential","authors":"R. Biswas , S. Mukhopadhyay , C. Sinha","doi":"10.1016/j.physb.2025.417091","DOIUrl":"10.1016/j.physb.2025.417091","url":null,"abstract":"<div><div>We investigated theoretically the transmission properties of Dirac Fermions tunneling through a periodically (sinusoidal and rectangular) driven electrostatic barrier in Monolayer graphene. For the time harmonic potential with moderate to high <span><math><mrow><mi>α</mi><mspace></mspace><mrow><mo>(</mo><mrow><mo>=</mo><msub><mi>V</mi><mn>0</mn></msub><mo>/</mo><mi>ℏ</mi><mi>ω</mi></mrow><mo>)</mo></mrow></mrow></math></span> the central Floquet band is found to be almost cloaked for the Klein transmitted electron in contrast to electron at higher grazing incidences. As a time periodic drive, we mainly focused on the use of rectangular wave electric signal to modulate the transparency of the barrier. It is noted that the asymmetric Fano resonance, a characteristic feature of photon assisted tunneling, is more likely to occur for rectangular drive in contrast to the harmonic one. The height of the modulating potential is particularly responsible for the dressing effect of the barrier. The position and nature of the FR can be tailored by changing the height and frequency of the rectangular drive. Moreover, the duty cycle of the driving potential turns out to be an important controlling parameter for the transmission process. Thus, the rectangular modulation plays an important role for the occurrence and detection of the Fano resonances which is vital for the use of graphene nanostructure in the field of detectors, sensors, modulators etc. The present work attempts for the first time, to realize the effect of duty cycle on the quantum interference in semiconductor nanostructures.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417091"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529308","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}
Iron oxide-aluminium oxide/reduced graphene oxide (FeOx-AlOx/rGO) nanocomposites (NCs) were synthesized using a chemically reduced process. The grain and crystallite sizes varied from 65 to 195 nm and 2.48–17.44 nm, respectively, with an increase in Al wt%. The rGO sheets showed hexagonal symmetry, as confirmed by the SAED pattern of the rGO sheets appearing with three concentric circles. UV–Vis spectra revealed that optical absorption was a red shift from 367.09 to 273.76 nm with increased AlOx concentration. The sp3 to sp2 carbon ratio, ID/IG, increases from 1.16 to 1.36 from 0 to 50 wt% AlOx decreased to 1.19 for the further increment of AlOx. The degree of passivation, ID1/IG and degree of stacking fault, ID3/IG, decreased from 0.55 to 0.23 and 0.24 to 0.08 for FeOx/rGO and (FeOx)0.25-(AlOx)0.75/rGO respectively, further increased to 0.33 and 0.32 for AlOx/rGO NC, respectively. The degree of dislocation, ID2/IG, decreased from 0.55 to 0.07, reducing the defects in the graphene structure by increasing AlOx wt.% of (FeOx)0.5-(AlOx)0.5/rGO NC. The highest specific capacitance, Csp is observed at 434 and 292.95 F g−1 for (FeOx)0.75-(AlOx)0.25/rGO NC by cyclic voltammetry and galvanostatic charge-discharge measurements, respectively. Maximum Cdl and minimum Rct of 3.04 × 10−9 Fg−1 and 120.93 Ω were observed for 75 wt% of AlOx content. The protective layer of FeOx prevents corrosion by acting as an inhibitor in the 1 M H2SO4 electrolytic solution. Moreover, the semi-empirical electronic environment of elements was explained using core orbital spectra.
{"title":"Electronic environments, optical and electrochemical properties of FeAlOx/reduced graphene oxide nanocomposites","authors":"Sumitra Dutta , Aishwarya Madhuri , Sanketa Jena , Soumyadeep Laha , Bibhu P. Swain","doi":"10.1016/j.physb.2025.417078","DOIUrl":"10.1016/j.physb.2025.417078","url":null,"abstract":"<div><div>Iron oxide-aluminium oxide/reduced graphene oxide (FeO<sub>x</sub>-AlO<sub>x</sub>/rGO) nanocomposites (NCs) were synthesized using a chemically reduced process. The grain and crystallite sizes varied from 65 to 195 nm and 2.48–17.44 nm, respectively, with an increase in Al wt%. The rGO sheets showed hexagonal symmetry, as confirmed by the SAED pattern of the rGO sheets appearing with three concentric circles. UV–Vis spectra revealed that optical absorption was a red shift from 367.09 to 273.76 nm with increased AlO<sub>x</sub> concentration. The sp<sup>3</sup> to sp<sup>2</sup> carbon ratio, I<sub>D</sub>/I<sub>G,</sub> increases from 1.16 to 1.36 from 0 to 50 wt% AlO<sub>x</sub> decreased to 1.19 for the further increment of AlO<sub>x</sub>. The degree of passivation, I<sub>D1</sub>/I<sub>G</sub> and degree of stacking fault, I<sub>D3</sub>/I<sub>G,</sub> decreased from 0.55 to 0.23 and 0.24 to 0.08 for FeO<sub>x</sub>/rGO and (FeO<sub>x</sub>)<sub>0.25</sub>-(AlO<sub>x</sub>)<sub>0.75</sub>/rGO respectively, further increased to 0.33 and 0.32 for AlO<sub>x</sub>/rGO NC, respectively. The degree of dislocation, I<sub>D2</sub>/I<sub>G,</sub> decreased from 0.55 to 0.07, reducing the defects in the graphene structure by increasing AlOx wt.% of (FeO<sub>x</sub>)<sub>0.5</sub>-(AlO<sub>x</sub>)<sub>0.5</sub>/rGO NC. The highest specific capacitance, C<sub>sp</sub> is observed at 434 and 292.95 F g<sup>−1</sup> for (FeO<sub>x</sub>)<sub>0.75</sub>-(AlO<sub>x</sub>)<sub>0.25</sub>/rGO NC by cyclic voltammetry and galvanostatic charge-discharge measurements, respectively. Maximum C<sub>dl</sub> and minimum R<sub>ct</sub> of 3.04 × 10<sup>−9</sup> Fg<sup>−1</sup> and 120.93 Ω were observed for 75 wt% of AlO<sub>x</sub> content. The protective layer of FeO<sub>x</sub> prevents corrosion by acting as an inhibitor in the 1 M H<sub>2</sub>SO<sub>4</sub> electrolytic solution. Moreover, the semi-empirical electronic environment of elements was explained using core orbital spectra.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417078"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526890","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 : 2025-02-27DOI: 10.1016/j.physb.2025.417094
Ziqiang Shuai , Qiubo Hu , Tongxin Zhao , Bingbing Zheng , Jianuo Song , Yuchu Jiang , Guanbo Zhao , Guangcai Sun , Jia Liu , Xuetong Guo
Microcrystalline silicon (μc-Si) thin films are prepared through plasma enhanced chemical vapor deposition (PECVD) route under the assist of negative bias. A substrate temperature as low as 150 °C is applied during deposition. Various characterizations have been carried out for investigating the structural, electrical and optical properties of the as-deposited thin films. At H2 flow = 600 sccm, the largest μc-Si grain size of ∼300–600 nm is obtained. Furthermore, HIT solar cell devices have been prepared for verifying the effect of P-doped μc-Si thin films as the n layer.
{"title":"Properties of phosphorous-doped large-grained microcrystalline silicon thin film and the application on HIT solar cell","authors":"Ziqiang Shuai , Qiubo Hu , Tongxin Zhao , Bingbing Zheng , Jianuo Song , Yuchu Jiang , Guanbo Zhao , Guangcai Sun , Jia Liu , Xuetong Guo","doi":"10.1016/j.physb.2025.417094","DOIUrl":"10.1016/j.physb.2025.417094","url":null,"abstract":"<div><div>Microcrystalline silicon (μc-Si) thin films are prepared through plasma enhanced chemical vapor deposition (PECVD) route under the assist of negative bias. A substrate temperature as low as 150 °C is applied during deposition. Various characterizations have been carried out for investigating the structural, electrical and optical properties of the as-deposited thin films. At H<sub>2</sub> flow = 600 sccm, the largest μc-Si grain size of ∼300–600 nm is obtained. Furthermore, HIT solar cell devices have been prepared for verifying the effect of P-doped μc-Si thin films as the n layer.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417094"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143549897","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 : 2025-02-27DOI: 10.1016/j.physb.2025.417092
M.S. Al-Kotb, J.Z. Al-Waheidi, M.F. Kotkata
The study examined the effects of nanomorphologies on electrical conductivity, Raman modes, and photoluminescence in two ZnO films grown by oxidizing metallic Zn on glass substrates. The first film, ZnO-TH1, exhibited distinct nano-granules, while the second film, ZnO-TH2, displayed highly crystalline, chaotic nanostructures, indicating potential applications in optoelectronics. X-ray diffraction analysis revealed a hexagonal wurtzite structure with a space group of P63mc. The films' electrical conductivity was temperature-dependent, with thermally activated conduction and variable-range hopping as the primary conduction mechanisms. The near-edge absorption ratios and Urbach energies were associated with reduced structural disorder and defect energy levels. The orientation of low-dimensional ZnO nanostructures significantly influenced the position, shape, and width of Raman spectral bands. The synthesized ZnO demonstrates potential for solid-state LED applications due to its nanoscale morphologies.
{"title":"Structural and spectroscopic properties of ZnO thin films with chaotic surface nanostructures","authors":"M.S. Al-Kotb, J.Z. Al-Waheidi, M.F. Kotkata","doi":"10.1016/j.physb.2025.417092","DOIUrl":"10.1016/j.physb.2025.417092","url":null,"abstract":"<div><div>The study examined the effects of nanomorphologies on electrical conductivity, Raman modes, and photoluminescence in two ZnO films grown by oxidizing metallic Zn on glass substrates. The first film, ZnO-TH1, exhibited distinct nano-granules, while the second film, ZnO-TH2, displayed highly crystalline, chaotic nanostructures, indicating potential applications in optoelectronics. X-ray diffraction analysis revealed a hexagonal wurtzite structure with a space group of P6<sub>3</sub>mc. The films' electrical conductivity was temperature-dependent, with thermally activated conduction and variable-range hopping as the primary conduction mechanisms. The near-edge absorption ratios and Urbach energies were associated with reduced structural disorder and defect energy levels. The orientation of low-dimensional ZnO nanostructures significantly influenced the position, shape, and width of Raman spectral bands. The synthesized ZnO demonstrates potential for solid-state LED applications due to its nanoscale morphologies.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417092"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529307","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}
This study delves the structural, morphological, and electrochemical properties of Co21.2O32and Cu2CoO3 compounds for supercapacitor applications. X-ray diffraction (XRD) confirms the pure crystalline structures of Co21.2O32 (cubic, Fd-3m) and Cu2CoO3 (orthorhombic, Pmmn), with crystallite sizes of 35.925 nm and 29.518 nm, respectively. Field emission scanning electron microscopy (FESEM) reveals granular morphologies with average grain sizes of 559.67 nm for Co21.2O32and 676.98 nm for Cu2CoO3. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) confirm the elemental compositions and valence states, including the presence of oxygen vacancies that enhance electron hopping. Electrochemical analysis, including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), shows that Cu2CoO3 exhibits superior performance, with higher specific capacitance (1186 F g−1 at 1 A/g) and excellent cycling stability (85 % retention after 10,000 cycles). The addition of copper improves conductivity, charge storage, and long-term durability, making Cu2CoO3 a promising candidate for energy storage applications.
{"title":"Structural insights and electrochemical behavior of Co21.2O32 and Cu2CoO3for high-performance supercapacitor applications","authors":"Vankudothu Nagendar , Anusha Purnakanti , Obula Reddy Ankinapalli , Durga Prasad Pabba , Vasudeva Reddy Minnam Reddy , M. Sreenath Reddy","doi":"10.1016/j.physb.2025.417080","DOIUrl":"10.1016/j.physb.2025.417080","url":null,"abstract":"<div><div>This study delves the structural, morphological, and electrochemical properties of Co<sub>21.2</sub>O<sub>32</sub>and Cu<sub>2</sub>CoO<sub>3</sub> compounds for supercapacitor applications. X-ray diffraction (XRD) confirms the pure crystalline structures of Co<sub>21.2</sub>O<sub>32</sub> (cubic, <strong><em>Fd-3m</em></strong>) and Cu<sub>2</sub>CoO<sub>3</sub> (orthorhombic, <strong><em>Pmmn</em></strong>), with crystallite sizes of 35.925 nm and 29.518 nm, respectively. Field emission scanning electron microscopy (FESEM) reveals granular morphologies with average grain sizes of 559.67 nm for Co<sub>21.2</sub>O<sub>32</sub>and 676.98 nm for Cu<sub>2</sub>CoO<sub>3</sub>. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) confirm the elemental compositions and valence states, including the presence of oxygen vacancies that enhance electron hopping. Electrochemical analysis, including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS), shows that Cu<sub>2</sub>CoO<sub>3</sub> exhibits superior performance, with higher specific capacitance (1186 F g<sup>−1</sup> at 1 A/g) and excellent cycling stability (85 % retention after 10,000 cycles). The addition of copper improves conductivity, charge storage, and long-term durability, making Cu<sub>2</sub>CoO<sub>3</sub> a promising candidate for energy storage applications.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417080"},"PeriodicalIF":2.8,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143550477","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}
In this work, Gallium (Ga) doped CdO:Ga/p-Si heterojunction thin films are fabricated by spray pyrolysis technique. Optical study of CdO and CdO:Ga films showed that the transparency ranges from 78 % to 73 % in the near infrared (NIR) region. Both the CdO and CdO:Ga films are direct band gap semiconductor and the band gap widens for different thickness of thin films. The photoluminescence (PL) study of CdO:Ga films grown on p-Si substrate showed two emission peaks for excitation wavelength 400 nm which are due to exciton emission and the band to band transition. The carrier concentrations for the CdO and CdO:Ga are found of the order of 1020 cm−3 are the indication of n-type semiconductors. The rectifying diode behavior of the CdO:Ga/p-Si heterojunctions is confirmed by the Current-Voltage (I-V) characteristics. The good diode characteristics are revealed through the ideality factor and the C–V response of the heterostructures.
{"title":"Synthesis of gallium (Ga) doped CdO/p-Si heterojunction and evaluation of junction parameters","authors":"Abdur Rouf, Md Saifur Rahman, M. Mojibur Rahman, M.S.I. Sarker, M.K.R. Khan","doi":"10.1016/j.physb.2025.417043","DOIUrl":"10.1016/j.physb.2025.417043","url":null,"abstract":"<div><div>In this work, Gallium (Ga) doped CdO:Ga/<em>p</em>-Si heterojunction thin films are fabricated by spray pyrolysis technique. Optical study of CdO and CdO:Ga films showed that the transparency ranges from 78 % to 73 % in the near infrared (NIR) region. Both the CdO and CdO:Ga films are direct band gap semiconductor and the band gap widens for different thickness of thin films. The photoluminescence (PL) study of CdO:Ga films grown on <em>p</em>-Si substrate showed two emission peaks for excitation wavelength 400 nm which are due to exciton emission and the band to band transition. The carrier concentrations for the CdO and CdO:Ga are found of the order of 10<sup>20</sup> cm<sup>−3</sup> are the indication of <em>n</em>-type semiconductors. The rectifying diode behavior of the CdO:Ga/p-Si heterojunctions is confirmed by the Current-Voltage (I-V) characteristics. The good diode characteristics are revealed through the ideality factor and the C–V response of the heterostructures.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"706 ","pages":"Article 417043"},"PeriodicalIF":2.8,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143620149","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 : 2025-02-25DOI: 10.1016/j.physb.2025.417075
Wan Li , Nur Miza Atikah Zulkafli , Mohamad Hafiz Mamat , Muhamad Kamil Yaakob
Predicting the energy band gap for FAPbI3 and MAPbI3 halide perovskites using density functional theory (DFT) methods often faces several difficulties and challenges. We investigated the effects of spin-orbit coupling (SOC) and dispersion corrections in DFT calculations on the crystal structure, electronic, and optical properties of MAPbI3 and FAPbI3 perovskites. Our findings indicate that incorporating SOC into LDA and GGA-PBE calculations improves the accuracy of energy band gap predictions for FAPbI3 and MAPbI3 structures. Furthermore, we demonstrate that adding dispersion corrections to GGA-PBE + SOC calculations indirectly affects structural relaxation, thereby enhancing the accuracy and consistency of MAPbI3 and FAPbI3 band gap values, which aligns with experimental data. Our new DFT approach, based on the cost-effective GGA-PBE + SOC + TS/MBD functional, accurately reproduces the electronic properties of MAPbI3 and FAPbI3, providing enhanced accuracy and consistency in calculating the energy band gap.
{"title":"Revisiting the effects of spin-orbit coupling and dispersion correction on the structural and electronic properties of APbI3 (A=MA, FA) halide perovskite","authors":"Wan Li , Nur Miza Atikah Zulkafli , Mohamad Hafiz Mamat , Muhamad Kamil Yaakob","doi":"10.1016/j.physb.2025.417075","DOIUrl":"10.1016/j.physb.2025.417075","url":null,"abstract":"<div><div>Predicting the energy band gap for FAPbI<sub>3</sub> and MAPbI<sub>3</sub> halide perovskites using density functional theory (DFT) methods often faces several difficulties and challenges. We investigated the effects of spin-orbit coupling (SOC) and dispersion corrections in DFT calculations on the crystal structure, electronic, and optical properties of MAPbI<sub>3</sub> and FAPbI<sub>3</sub> perovskites. Our findings indicate that incorporating SOC into LDA and GGA-PBE calculations improves the accuracy of energy band gap predictions for FAPbI<sub>3</sub> and MAPbI<sub>3</sub> structures. Furthermore, we demonstrate that adding dispersion corrections to GGA-PBE + SOC calculations indirectly affects structural relaxation, thereby enhancing the accuracy and consistency of MAPbI<sub>3</sub> and FAPbI<sub>3</sub> band gap values, which aligns with experimental data. Our new DFT approach, based on the cost-effective GGA-PBE + SOC + TS/MBD functional, accurately reproduces the electronic properties of MAPbI<sub>3</sub> and FAPbI<sub>3</sub>, providing enhanced accuracy and consistency in calculating the energy band gap.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"704 ","pages":"Article 417075"},"PeriodicalIF":2.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143488019","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}
This study shows the effect of Cu alloying ZnO (CZO) films (x = 1–7 at.%) on their structural, electrical, and optical properties. ZnO:Cu was synthesized by the pulsed spray-pyrolysis technique using molecular solutions. CZO films were studied by XRD, SEM, EDX, Raman and optical spectroscopy, and Hall effect measurements. XRD analysis proves the formation of single-phase films with a hexagonal wurtzite structure, further confirmed by Raman spectroscopy. EDX analysis showed the successful incorporation of Cu in the unit cell of ZnO at the concentrations of x = (1–7) at.%. CZO film at x = 1 at.% possessed the best microstructure characteristics, i.e., L(100)= 22.4 nm; ε(100)= 5.9·10−3; ρεL(100) = 1.4·1016 lin∙m−2. It was found that the band gap, Eg = 3.32 eV, in the non-alloyed ZnO films is not significatively changed upon Cu alloying, residing in the range of (3.32–3.33) eV. The low resistivity (ρ = 7.14 Ω cm) and high Hall mobility (μ = 385.91 сm2/V⋅s) were observed for the CZO films at x = 1 at.%. Thus the obtained CZO films by using the pulsed spray-pyrolysis methodology could be of interest for application in solar cells as window and charge collection layers, as determined by their properties.
{"title":"Structural, optical, and electrical properties of copper-alloyed ZnO films deposited by the pulsed spray-pyrolysis with molecular solutions","authors":"Bohdan Boiko , Maksym Yermakov , Roman Pshenychnyi , Oleksii Klymov , Anatoliy Opanasyuk , Oleksandr Dobrozhan , Oleksii Diachenko , Vicente Muñoz-Sanjosé","doi":"10.1016/j.physb.2025.417086","DOIUrl":"10.1016/j.physb.2025.417086","url":null,"abstract":"<div><div>This study shows the effect of Cu alloying ZnO (CZO) films (<em>x</em> = 1–7 at.%) on their structural, electrical, and optical properties. ZnO:Cu was synthesized by the pulsed spray-pyrolysis technique using molecular solutions. CZO films were studied by XRD, SEM, EDX, Raman and optical spectroscopy, and Hall effect measurements. XRD analysis proves the formation of single-phase films with a hexagonal wurtzite structure, further confirmed by Raman spectroscopy. EDX analysis showed the successful incorporation of Cu in the unit cell of ZnO at the concentrations of <em>x</em> = (1–7) at.%. CZO film at <em>x</em> = 1 at.% possessed the best microstructure characteristics, <em>i.e.</em>, <em>L</em><sub>(100)</sub> <em>=</em> 22.4 nm; <em>ε</em><sub>(100)</sub> <em>=</em> 5.9·10<sup>−3</sup>; <em>ρ</em><sub><em>εL</em>(100)</sub> = 1.4·10<sup>16</sup> lin∙m<sup>−2</sup>. It was found that the band gap, <em>E</em><sub>g</sub> = 3.32 eV, in the non-alloyed ZnO films is not significatively changed upon Cu alloying, residing in the range of (3.32–3.33) eV. The low resistivity (<em>ρ</em> = 7.14 Ω cm) and high Hall mobility (<em>μ</em> = 385.91 сm<sup>2</sup>/V⋅s) were observed for the CZO films at <em>x</em> = 1 at.%. Thus the obtained CZO films by using the pulsed spray-pyrolysis methodology could be of interest for application in solar cells as window and charge collection layers, as determined by their properties.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417086"},"PeriodicalIF":2.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143519571","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}
The magnetic, lattice dynamical, and elastic properties of the Laves phases (C14, C15, and C36) and the orthorhombic (Imma) phase of YFe2 were investigated under ambient and high pressures using first-principles calculations. Below 86 GPa, the C15 and Imma phases exhibit higher thermodynamic stability compared to the C14 and C36 phases. However, the C14 phase becomes the most stable structure when the pressure exceeds 86 GPa. At ambient pressure, all Fe atoms in the C15, Imma, and C14 phases exhibit magnetic moments of approximately 2 μB, while Y atoms possess negative magnetic moments of about −0.5 μB, resulting in ferrimagnetism in all four phases. Notably, in the C36 structure, the magnetic moments of Fe atoms at the 6h site are antiparallel to those at other sites, with three reversals observed under pressures from 0 to 8 GPa. Elastic and dynamical analyses indicate that the C36 phase becomes unstable near 10 GPa, while the C14 phase is elastically unstable near 5 GPa but dynamically stable and brittle. The system shows negligible shear and compression resistance near these pressures but exhibits ductility at other pressure ranges. These findings provide new insights into the pressure-dependent properties of YFe2, offering guidance for its potential applications under varying pressure conditions.
{"title":"Pressure-induced anomalous properties of Laves phase and orthorhombic phase of YFe2","authors":"Huang-yan Cheng, Xin-xin Zhang, Guo-liang Yu, Tai-min Cheng","doi":"10.1016/j.physb.2025.417088","DOIUrl":"10.1016/j.physb.2025.417088","url":null,"abstract":"<div><div>The magnetic, lattice dynamical, and elastic properties of the Laves phases (C14, C15, and C36) and the orthorhombic (<em>Imma</em>) phase of YFe<sub>2</sub> were investigated under ambient and high pressures using first-principles calculations. Below 86 GPa, the C15 and <em>Imma</em> phases exhibit higher thermodynamic stability compared to the C14 and C36 phases. However, the C14 phase becomes the most stable structure when the pressure exceeds 86 GPa. At ambient pressure, all Fe atoms in the C15, <em>Imma</em>, and C14 phases exhibit magnetic moments of approximately 2 <em>μ</em><sub>B</sub>, while Y atoms possess negative magnetic moments of about −0.5 <em>μ</em><sub>B</sub>, resulting in ferrimagnetism in all four phases. Notably, in the C36 structure, the magnetic moments of Fe atoms at the 6h site are antiparallel to those at other sites, with three reversals observed under pressures from 0 to 8 GPa. Elastic and dynamical analyses indicate that the C36 phase becomes unstable near 10 GPa, while the C14 phase is elastically unstable near 5 GPa but dynamically stable and brittle. The system shows negligible shear and compression resistance near these pressures but exhibits ductility at other pressure ranges. These findings provide new insights into the pressure-dependent properties of YFe<sub>2</sub>, offering guidance for its potential applications under varying pressure conditions.</div></div>","PeriodicalId":20116,"journal":{"name":"Physica B-condensed Matter","volume":"705 ","pages":"Article 417088"},"PeriodicalIF":2.8,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526891","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}
扫码关注我们
求助内容：
应助结果提醒方式：
京公网安备 11010802042870号