Current Applied Physics最新文献

{"title":"Exploring phase transition dynamics in VO2 films: The role of substrate temperature","authors":"Akash Kumar Singh ,&nbsp;Deependra Kumar Singh ,&nbsp;H.K. Singh ,&nbsp;P.K. Siwach","doi":"10.1016/j.cap.2025.05.006","DOIUrl":"10.1016/j.cap.2025.05.006","url":null,"abstract":"<div><div>We investigated the effect of substrate temperature (T_S) on the phase transition characteristics of RF sputtered VO₂ films deposited on hexagonal ALO (0001) and cubic YSZ (001) substrates at ∼500°C–800 °C under Ar ambient only, in correlation with structure and morphology. High-Resolution X-ray Diffraction (HRXRD) and Raman spectroscopy confirmed the formation of the polycrystalline VO₂ (M1) phase with traces of secondary phases. Atomic Force Microscopy (AFM) and Field Emission Electron Microscopy (FESEM) reveal distinct surface roughness and grain morphology. Surface roughness increases significantly with large and non-uniform grains on c-plane Sapphire (ALO), whereas on Yttria-stabilized zirconia (YSZ), grains are small and uniform, having minimal surface roughness variation with increasing temperature. Above 600 °C, VO₂ films on both substrates exhibit reversible insulator-metal transitions (IMT/MIT) with ∼ (3–4) order resistivity change and pronounced thermal hysteresis close to ∼340K. The transition temperature (T_C) decreases with minima at ∼700 °C and again increases with temperature. Hysteresis width increases on ALO (∼1K–∼10K), whereas it decreases on YSZ (∼14K–∼7K) with increasing temperature. Films on both substrates above ∼600 °C exhibit room temperature average Temperature Coefficient of Resistance (TCR) of ∼ (1.61–3.18 %K⁻¹) and warming peak TCR of ∼(54.30–85.39 %K⁻¹ on ALO) and ∼(85.31–98.02 %K⁻¹ on YSZ). Distinct Activation Energy (E_A) dependence on substrate type and temperature has been observed in metallic and insulating phases. The observed phase transition characteristics of VO₂ films have been explained based on variation in distinct structure and morphology, which strongly depends on substrate type and temperature. These findings anticipate that substrate type and temperature play a decisive role in tailoring the structural and phase transition characteristics of VO₂ films for potential applications.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"76 ","pages":"Pages 45-57"},"PeriodicalIF":2.4,"publicationDate":"2025-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144155162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Enhancing photovoltaic performance of flower-like MoS2@ZnO core-shell nanowire photoanodes: Synergistic effects on solar energy conversion","authors":"Alagumalai Manimekalai ,&nbsp;Kuppu Sakthi Velu ,&nbsp;Sonaimuthu Mohandoss ,&nbsp;Seho Sun","doi":"10.1016/j.cap.2025.05.003","DOIUrl":"10.1016/j.cap.2025.05.003","url":null,"abstract":"<div><div>This study introduces an innovative flower-like molybdenum sulfide (MoS₂)-doped zinc oxide (ZnO) core-shell nanowire (NWs) designed to enhance the efficiency of dye-sensitized solar cells (DSSCs). The MoS2@ZnO NWs, created via a simple hydrothermal method, exhibit flower-like structures that improve light absorption and charge separation. Surface morphology analyses using FE-SEM, HR-TEM, and AFM confirm the core-shell architecture of the NWs, while XRD patterns reveal a hexagonal wurtzite phase with a distinct (003) plane. Electrical conductivity studies show that MoS2@ZnO NWs achieve a high conductivity of 3.65 × 10⁻³ S cm⁻¹. DSSCs were assembled with ZnO NPs and MoS2@ZnO NWs as photo-anodes and iodide/tri-iodide redox mediator solution, along with platinum (Pt) as the counter electrode (CE). The MoS₂@ZnO photo-anode attained a promising efficiency of 7.25 %, compared to 4.07 % from pristine ZnO NPs, highlighting the potential of core-shell NWs for advanced solar Cell applications.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"76 ","pages":"Pages 7-15"},"PeriodicalIF":2.4,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Design and application of multi-absorption and highly sensitive monolayer graphene microstructure absorption devices located at terahertz frequencies","authors":"Xuncen Guo ,&nbsp;Chaojun Tang ,&nbsp;Zao Yi ,&nbsp;Shubo Cheng ,&nbsp;Junqiao Wang ,&nbsp;Boxun Li","doi":"10.1016/j.cap.2025.05.005","DOIUrl":"10.1016/j.cap.2025.05.005","url":null,"abstract":"<div><div>A graphene absorber has been designed in this message that is based on surface plasmon resonance (SPR). <u>The absorber exhibits four perfect absorption peaks within the target frequency band, featuring an innovative structure with excellent tunability and incident-angle insensitivity. The absorber features a triple-layered framework, with a gold (Au) substrate as the bottom layer, a silica (SiO</u>₂<u>) layer serving as the medium layer in the middle, and a graphene layer in a “#” symbol shape at the top.</u> The absorber has a simple structure and is easy to fabricate. <u>We then analyzed four variant that the absorber displays peak absorption efficiencies of 99.99 %, 99.32 %, 99.71 %, and 99.99 % when the frequencies are 7.5005 THz, 9.0920 THz, 10.1181 THz, and 11.3193 THz, respectively, all exceeding 99 %, demonstrating excellent absorption performance.</u> Additionally, we set up four electric field monitors to plot the electric field energy distribution maps for the four absorption peaks. <u>We then analyzed four variant structures derived from the original design, comparing the number of absorption peaks, absorption rates, and sensitivity, and concluded that the model structure proposed in this study is optimal.</u> After changing Fermi degree and time of relaxation, adjustment of the waves can be realized. The absorber demonstrates insensitivity to the angle as the incidence angle is changed from 0° to 60°. Furthermore, with the change of environmental refractive index, the maximum sensitivity among peaks can reach 3586 THz/RIU, showcasing high sensitivity. Finally, we calculated the figure of merit (FOM) and quality factor (Q) values for our model, which we compared with those of other absorbers, concluding that our absorber performs exceptionally well in terms of FOM and Q values. <u>Given these advantages, the absorber designed in this paper can be used in fields of sensors etc.</u></div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"76 ","pages":"Pages 16-25"},"PeriodicalIF":2.4,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Structural and electronic properties of oxygen adsorption on TiN(001) surfaces: A first-principles study","authors":"Jinwoo Park,&nbsp;Junjin Jeon,&nbsp;Byung Deok Yu","doi":"10.1016/j.cap.2025.05.002","DOIUrl":"10.1016/j.cap.2025.05.002","url":null,"abstract":"<div><div>Using first-principles electronic structure calculations, we investigated the adsorption of oxygen atoms on TiN(001) surfaces at various oxygen coverages. The average adsorption energy calculations reveal that the <span><math><mi>p</mi><mo>(</mo><mn>1</mn><mo>×</mo><mn>2</mn><mo>)</mo></math></span> surface reconstruction featuring the fourfold coordination of titanium with two nitrogen and two oxygen atoms, previously suggested at an oxygen coverage of 0.50 monolayer, is energetically favorable under ultrahigh vacuum conditions. Utilizing <em>ab-initio</em> atomic thermodynamics, we also present a temperature-pressure phase diagram for surface stability under oxygen gas environmental conditions. The electronic properties of these surfaces are analyzed through projected electronic density of states and work function calculations. Furthermore, we provide simulated scanning tunneling microscopy images for each stable surface configuration to aid experimental observations.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"76 ","pages":"Pages 1-6"},"PeriodicalIF":2.4,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144072250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Electron-beam-induced tunable reduction of graphene oxide on cellulose-based filter paper for flexible electromagnetic interference shielding","authors":"Jagdeep Singh ,&nbsp;Santosh K. Tiwari ,&nbsp;Soumik Bhowmik ,&nbsp;Karan Singh Hada ,&nbsp;A.S. Dhaliwal","doi":"10.1016/j.cap.2025.05.004","DOIUrl":"10.1016/j.cap.2025.05.004","url":null,"abstract":"<div><div>This study reports the electrochemical exfoliation synthesis of graphene oxide (GO) and the fabrication of free-standing GO films via vacuum filtration on cellulose filter paper (CFP). The films were subjected to electron beam irradiation at 10 keV for varying durations to achieve controlled reduction to reduced graphene oxide (rGO). Comprehensive characterization revealed significant changes in optical, thermal, chemical, morphological, mechanical, and dielectric properties, confirming successful reduction. The resulting rGO/CFP composite was used as electromagnetic interference (EMI) shielding in the 4–14 GHz range. Notably, the film was irradiated for 90 min, exhibiting a shielding effectiveness of 60.8 dB at 10 GHz with a thickness of 0.32 mm. This enhancement is attributed to improved conductivity, polarization relaxation, and dielectric losses caused by hopping carriers and lattice defects. E-beam irradiation presents a chemical-free, efficient method for producing flexible, high-performance rGO/CFP films for EMI shielding.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"75 ","pages":"Pages 50-62"},"PeriodicalIF":2.4,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143947282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Exploring structural, optical, and magnetic analysis of dilute Co incorporated CdS thick films for spintronics","authors":"Aeshah Alasmari ,&nbsp;Salma Alshehri ,&nbsp;Abdulaziz Almalki ,&nbsp;Fahad Algarni ,&nbsp;Hosam M. Gomaa ,&nbsp;F.M. Aldosari ,&nbsp;Atef Ismail","doi":"10.1016/j.cap.2025.04.009","DOIUrl":"10.1016/j.cap.2025.04.009","url":null,"abstract":"<div><div>This study involves the preparation using a solid-state reaction method of six thin films of Cd_1-xCo_xS by varying the concentrations of cobalt and cadmium, where x = 0.0, 0.02, 0.04, 0.06, 0.08, and 0.1 At. %. The process included mixing Co₂S₃ and CdS powders in stoichiometric ratios, followed by mechanical ball milling, compacting into discs, and analyzing the films' properties. X-ray diffraction (XRD) confirmed the films' crystalline structure and energy-dispersive X-ray spectroscopy (EDX) verified the elemental composition, indicating the successful incorporation of Co into the CdS matrix. X-ray photoelectron spectroscopy (XPS) further detailed the chemical states within the films, showing that Co substitution influenced optical properties. The films' optical transmittance decreased with higher Co content, while reflectance and absorption increased, attributed to Co's impact on the electronic structure. The study also demonstrated a decrease in crystallite size and an increase in lattice strain with rising Co concentration, suggesting a reduction in crystallinity. Optical analyses revealed a decrease in the energy band gap and an increase in refractive index as Co content increased. The refractive index was modeled using the Cauchy equation, and the study noted a corresponding rise in static refractive index and dielectric constant, implying enhanced electromagnetic energy storage capability. Additionally, the magnetic properties showed room-temperature ferromagnetism (RT-FM) across all films, with significant values for saturation magnetization, coercivity, and retentivity.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"75 ","pages":"Pages 40-49"},"PeriodicalIF":2.4,"publicationDate":"2025-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143931571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Delta-function-potential junctions with quasiparticles occupying tilted bands with quadratic-in-momentum dispersion","authors":"Ipsita Mandal","doi":"10.1016/j.cap.2025.04.007","DOIUrl":"10.1016/j.cap.2025.04.007","url":null,"abstract":"<div><div>We continue our explorations of the transport characteristics in junction-configurations comprising semimetals with quadratic band-crossings, observed in the bandstructures of both two- and three-dimensional materials. Here, we consider short potential barriers/wells modelled by delta-functions. We also generalize our analysis by incorporating tilts in the dispersion. Due to the parabolic nature of the spectra, caused by quadratic-in-momentum dependence, there exist evanescent waves, which decay exponentially as we move away from the junction represented by the location of the delta-function potential. Investigating the possibility of the appearance of bound states, we find that their energies appear as pairs of <span><math><mo>±</mo><mo>|</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>b</mi></mrow></msub><mo>|</mo></math></span>, reflecting the presence of the imaginary-valued wavevectors at both positive and negative values of energies of the propagating quasiparticles.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"76 ","pages":"Pages 26-38"},"PeriodicalIF":2.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144090515","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Thickness dependence of surface Rashba spin-momentum coupling","authors":"Byeonghyeon Choi,&nbsp;Jeonghun Sohn,&nbsp;Hyun-Woo Lee","doi":"10.1016/j.cap.2025.04.006","DOIUrl":"10.1016/j.cap.2025.04.006","url":null,"abstract":"<div><div>Here we present findings indicating that Rashba spin-momentum coupling (RSMC), traditionally believed to be confined within the Fermi wavelength from the surface, displays a thickness dependence in metallic thin films. Specifically, we observed that in Au films thinner than a critical thickness of 4 nm, and in Pt films thinner than 5 nm, quantum interference occurs between the top and bottom surface states, strongly impacting the surface spin polarization. The spin polarization gradually increases with the film thickness until it reaches these critical thresholds, beyond which it saturates. Our findings serve as examples illustrating that the characteristic length of RSMC far exceeds the Fermi wavelength, while the characteristic length has been regarded as the Fermi wavelength in spin-orbit torque measurements.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"75 ","pages":"Pages 28-32"},"PeriodicalIF":2.4,"publicationDate":"2025-05-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143921605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"TRANSFERLESS soft-lithography for the fabrication of peristaltic micropump with dome-shape membrane","authors":"Ayub Subandi ,&nbsp;Muhamad Ramdzan Buyong ,&nbsp;Azrul Azlan Hamzah ,&nbsp;Rhonira Latif ,&nbsp;Burhanuddin Yeop Majlis ,&nbsp;Roer Eka Pawinanto ,&nbsp;Budi Mulyanti ,&nbsp;Jumril Yunas","doi":"10.1016/j.cap.2025.04.008","DOIUrl":"10.1016/j.cap.2025.04.008","url":null,"abstract":"<div><div>This paper reports a new technique for fabricating a polydimethylsiloxane (PDMS)-based peristaltic electromagnetic (EM) micropump with a dome-shaped membrane structure. The membrane was intended to allow a high rate of fluid sample transport. A new and effective soft-lithography process without the transfer of mold structures is introduced, which is used for forming dome-shaped membranes, microfluidic channels, and pump chambers. This technique includes four main steps, membrane fabrication, pattern of the first and second PDMS mold, removal of the photoresist inside the channel and finally attachment of the EM coils. The coating properties and surface quality were analyzed using scanning electron microscopy (SEM). The results showed that the membrane and channels was formed properly without any leakage. The fabricated actuator was functionally tested to determine the performances of the micropump. Polymer-based microfluidic pump systems have potential applications in precisely injection of microfluidic samples in artificial kidney and smart insulin drug delivery system.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"75 ","pages":"Pages 15-20"},"PeriodicalIF":2.4,"publicationDate":"2025-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143908273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}

{"title":"Fabrication of AlGaN/GaN HEMT using TMAH pre-treatment and analysis of electrical characteristics by proton irradiation","authors":"Jin Park ,&nbsp;Sang Ho Lee ,&nbsp;In Man Kang ,&nbsp;Young Jun Yoon","doi":"10.1016/j.cap.2025.04.010","DOIUrl":"10.1016/j.cap.2025.04.010","url":null,"abstract":"<div><div>In this study, we analyzed the effects of proton irradiation and surface pre-treatment on gallium nitride (GaN)-based high electron mobility transistors (HEMTs) and evaluated their reliability against proton irradiation. The variation in DC performance of the AlGaN/GaN HEMT was analyzed by irradiating a proton energy of 15 MeV at proton fluence of 5 × 10¹³ cm⁻². During the pre-treatment process, the active region and mesa isolation region (Sample 1) and mesa isolation region (Sample 2) were treated with trimethylammonium (TMAH) solution, respectively. And the variation in transfer characteristics of before and after proton irradiation were compared. In terms of transfer characteristics of before and after proton irradiation, the drain current decreased after proton irradiation due to increase the sheet resistance and contact resistance. Also, acceptor-like and donor-like vacancies were generated on the AlGaN/GaN surface due to proton irradiation, inducing the displacement damage effect. In particular, the variation in on current (I_on) increased by 7.26 percentage point (%p) when TMAH treatment in the Sample 2 compared to when TMAH treatment in the Sample 1 after proton irradiation. The damage caused by dry etching and plasma-enhanced chemical vapor deposition (PECVD) plasma enhanced the proton irradiation effect because the AlGaN/GaN surface was not completely treated by the TMAH solution due to SiN deposition. These results demonstrate that the radiation hardness of GaN-based HEMTs is affected by the AlGaN/GaN surface quality and pre-treatment using TMAH solution is necessary to increase the resistance to proton irradiation.</div></div>","PeriodicalId":11037,"journal":{"name":"Current Applied Physics","volume":"75 ","pages":"Pages 33-39"},"PeriodicalIF":2.4,"publicationDate":"2025-05-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143928136","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}