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Influence of substrate and substrate temperature on the structural, optical and surface properties of InGaN thin films prepared by RFMS method
摘要： In this work, the pure InGaN thin films were grown using n-type and p-type silicon substrates at varying substrate temperatures using the sputtering method. The effects of substrate and substrate temperature on the structural, morphological and optical properties of the thin films grown were investigated. X-ray diffraction (XRD) analyzes of the obtained films illustrates crystal structures at C substrate temperature, the films were found to be hexagonal. Scanning electron microscopy (SEM) was used to investigate the shape, size and surface distribution of the particles formed on film surfaces. The reflection and optical band gap (Eg) of the films were investigated from the optical analyzes taken with the UV-VIS spectrophotometer. As a result of these analyzes, it has been reached that the substrate and substrate temperature have a great influence on the structural, morphological and optical properties of the films. The experimental findings obtained in the study are compared with the studies given in the literature and the similarities and differences are discussed.
关键词： InGaN growth,silicon substrate,thin films,sputtering technique,substrate temperature
更新于2025-09-23 15:23:52
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Sensing Properties of the <I>N</I>,<I>N</I>′-Dipentyl-3,4,9, 10-Perylenedicarboximide Small Molecule for Different Concentrations and Solvents for Sensor Applications
摘要： In present study, optical parameters based on refractive index of the PTCDI-C5 molecule were calculated using the single oscillator model. Also, significant parameters such as long wavelength refractive index, average oscillator wavelength, lattice dielectric constant, ratio of the carrier concentration to the electron effective mass, carrier concentration and electron effective mass of the PTCDI-C5 molecule were obtained. Then, sensing properties of the PTCDI-C5 molecule for different concentrations and volume percents were investigated and the effects of the concentrations and volume percents on sensing parameters were investigated. Then, the optical properties of the solutions of the PTCDI-C5 semiconductor for different solvents were investigated. Finally, these parameters obtained were discussed for sensor applications and this study was compared with the similar and related studies in the literature. PTCDI-C5 can be used in the fabrication of various sensors due to good soluble, optical, sensitivity and response behaviour.
关键词： Wemple DiDomenico Technique,Sensor Applications,PTCDIC5,One Dimensional Organic Nanostructures,Sensing Parameters,Sensitivity
更新于2025-09-23 15:23:52
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Prediction of First Higher Order Modal Field for Graded Index Fiber in Presence of Kerr Nonlinearity
摘要： We report evaluation of first higher order modal field for dual mode optical fiber having step and parabolic index profiles. The study is carried out both in absence as well as in presence of Kerr nonlinearity. The analysis is based on a simple iterative method involving Chebyshev formalism. Taking some typical step- and parabolic-index fibers as examples, we show that our results agree excellently with the exact results which can be obtained by applying rigorous methods. Thus, our simple formalism stands the merit of being considered as an accurate alternative to the existing cumbersome methods. The prescribed formalism provides scope for accurate estimation of different propagation parameters associated with first higher order mode in such kinds of fibers in presence of Kerr nonlinearity. The execution of formalism being user friendly, it will be beneficial to the system engineers working in the field of optical technology.
关键词： first higher order modal field,dual mode graded-index fiber,Kerr nonlinearity,Chebyshev technique
更新于2025-09-23 15:23:52
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Effects of Withdrawal Speeds on Properties of ZnO Thin Films Prepared by Sol-Gel Immerse Technique
摘要： ZnO thin films have attractive applications in photoelectric device, due to their excellent chemical, electrical and optical properties. In this paper, ZnO thin films with good c-axis preferred orientation and high transmittance are prepared on glass sheets by sol-gel immerse technique. The effects of withdrawal speeds on the growth process of thin film crystal, film crystal orientation and the crystallinity, the optical performance were investigated by XRD, SEM and UV-Vis spectrophotometry. The results show that the thin films were composed of better hexagonal wurtzite crystals with the c-axis prepared orientation. The transmittance of prepared thin films is over 80% in the visible-near IR region from 600 nm - 800 nm. ZnO films have sharp and narrow diffraction peaks, which indicates that the materials exhibit high crystallinity. With the withdrawal speeds increasing, the grain size of ZnO thin films and the intensity for all diffraction peaks were increased gradually. The growth model is changed from the stratified structure into the island structure in the growth process. The transmittance of the thin films decrease in the visible wavelength region, with the withdrawal speeds increasing.
关键词： Withdrawal speeds,ZnO thin film,C-axis preferred orientation,Sol-gel technique
更新于2025-09-23 15:23:52
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An Eco-friendly Flexible Piezoelectric Energy Harvester That Delivers High Output Performance is Based on Lead-Free MASnI3 Films and MASnI3-PVDF Composite Films
摘要： An environmentally-friendly lead-free methylammonium tin iodide (MASnI3) perovskite is successfully synthesized using a facile approach of an antisolvent-assisted collision technique under room ambient conditions, which results stability within 24 h under ambient room conditions. The phase transition of MASnI3 from tetragonal to cubic is first observed at ~ 30 °C. Polycrystalline MASnI3 films reveal a high dielectric constant of ~ 65 at 100 kHz, a low-leakage current density of 7 × 10-7 A cm-2 at 50 kV cm-1, well-developed P-E hysteresis loops, and a high piezoelectric coefficient (d33) of 20.8 pm V-1. The MASnI3 piezoelectric energy nanogenerator (PENG) shows an output voltage of ~ 3.8 V and an output current density of 0.35 μA cm-2. To enhance the piezoelectric output performance, the MASnI3 films are composited with an environmentally friendly PVDF polymer that had a porous structure. The PVDF-MASnI3 composite based-PENG reveals a maximum output voltage of ~ 12.0 V and current density of ~ 4.0 μA cm-2. A green light-emitting diode (LED) using the PVDF-MASnI3 PENGs is instantly lighted without need of a storage device, and long-term stability of the composite PENGs is validated for 90 days. This simple and cost-effective solution process is feasible for the fabrication of large-scale, high-performance, and environmental-friendly PENGs based on lead-free organic-inorganic perovskites to extensively implicate in medical and biomechanical applications.
关键词： Dielectric property,Lead-free MASnI3,PVDF-MASnI3 composite PENGs,Piezoelectric energy,Antisolvent-assisted collision technique
更新于2025-09-23 15:23:52
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AIP Conference Proceedings [Author(s) 4TH ELECTRONIC AND GREEN MATERIALS INTERNATIONAL CONFERENCE 2018 (EGM 2018) - Bandung, Indonesia (27–28 July 2018)] - Design and analysis of fiber Bragg grating tunable filter utilizing thermal technique
摘要： In this paper a tunable filter based on fiber Bragg grating (FBG) utilizing thermal technique is theoretically investigated and experimentally validated. According to the results, a tuning range is achieved about 1.5 nm in C-band region. While, for L-band region the wavelength shift is slightly greater than in the C-band region about 1.6 nm. This shifting is due to changing in thermo-optic and thermal expansion of fiber, which causes changing in refractive index and then Bragg wavelength. The experimental validation is done at wavelength 1552.7 nm, the tunability is about 1.2428 nm when the temperature is varied from 21°C to 61°C.
关键词： thermal expansion,fiber Bragg grating,thermo-optic effect,thermal technique,tunable filter
更新于2025-09-23 15:23:52
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[IEEE 2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM) - Waterloo, ON (2018.8.19-2018.8.22)] 2018 18th International Symposium on Antenna Technology and Applied Electromagnetics (ANTEM) - Cavity Perturbation Technique to Characterize Dielectric Materials at Ka-band
摘要： The characterization of permittivity and dielectric loss of dielectric materials using a perturbation technique is conducted in simulation. The working frequency of this technique has been extended to the Ka-band. Simulation results demonstrate this perturbation technique is suitable for characterization of high permittivity dielectric materials for mm-wave and maintains good accuracy.
关键词： dielectric loss measurement,permittivity measurement,cavity perturbation technique,dielectric materials,Ka-band
更新于2025-09-23 15:23:52
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[IEEE 2018 18th International Symposium on Communications and Information Technologies (ISCIT) - Bangkok, Thailand (2018.9.26-2018.9.29)] 2018 18th International Symposium on Communications and Information Technologies (ISCIT) - Weapon Detector System by Using X-ray Image Processing Technique
摘要： The images in the research were obtained from the internet because there is no x-ray camera. After preparing images, the next step is to test that the evaluation used to analyze the suspicious images. The images were detected by Canny Edge Detector algorithm that consists of four steps that started by smoothing the images with a Gaussian filter to eliminate interfering signals. Then, it calculated magnitude and orientation of gradient. Non-maxima Suppression and Gradient Magnitude were used to create thinner edges. The last step is double threshold algorithm to identify edge pixels and connect the edges by optimizing image recognition technique. When detecting a suspicious object, the system would send the notification. The result of this project is that the template matching algorithm was 80% accurate.
关键词： Detector,Vehicle,X-ray,Technique,Weapon
更新于2025-09-23 15:22:29
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Leakage Mitigation in Heterodyne FMCW Radar for Small Drone Detection With Stationary Point Concentration Technique
摘要： To prevent potential hazards posed by fast-evolving drones, it is of importance to develop a radar system for drone detection. Frequency modulated continuous wave (FMCW) radars are widely used for that purpose. Heterodyne architectures are preferred for them to mitigate dc offset errors. Having said that, FMCW radars suffer from permanent leakage from the transmitter into the receiver. The leakage phase noise raises the total noise floor and limits the radar sensitivity. Here, we propose a stationary point concentration (SPC) technique in order to overcome the challenges. The SPC technique concentrates the leakage phase noise on a stationary point to alleviate the impact of the noise. The technique can be realized using digital signal processing without additional hardware. The results show that the proposed technique significantly lowers the noise floor.
关键词： heterodyne,down-conversion,leakage,digital signal processing (DSP),frequency modulated continuous wave (FMCW) radar,stationary point concentration (SPC) technique,stationary point,phase noise,noise floor
更新于2025-09-23 15:22:29
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Domain imaging in Fe-doped KNbO3 single crystal via trinocular microscopy and scanning electron microscopy
摘要： Trinocular microscopy with a high spatial resolution is a promising technique for studying the surface morphology of materials. The cleavage face of ferroelectric Fe-doped K niobate (KNbO3) crystals was chemically etched by using HNO3. Trinocular microscopy was used to study the surface morphology of the grown ferroelectric KNbO3 single crystals. The grown surface of the crystal with a 60° domain wall revealed the same interaction and orientations. The results indicate that the type of domain walls that occur in ferroelectric crystals depend on the symmetry of both the nonferroelectric and ferroelectric phases of the crystal.
关键词： Trinocular microscopy,Single crystal,Etching technique,Domain wall
更新于2025-09-23 15:22:29