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AIP Conference Proceedings [AIP Publishing SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019 - Erode, India (21–22 November 2019)] SECOND INTERNATIONAL CONFERENCE ON MATERIAL SCIENCE, SMART STRUCTURES AND APPLICATIONS: ICMSS-2019 - Modeling of optical characteristics of near-infrared photodetectors on the basis of InAs/GaAs heterointerfaces
摘要： A mathematical model for simulation of optical and functional characteristics of InAs/GaAs heterointerfaces with one layer of InAs quantum dots has been developed. The presence of the peak of the main optical transitions in quantum dots of 1.2 eV (modeling) and 1.12 eV (experimental) is demonstrated. The experimental photoluminescence peak has a greater width (0.13 eV) at half the maximum radiation of the main transitions in quantum dots compared to the simulated one (0.06 eV). A red shift of the experimental peak by approximately 65 meV is observed, which indicates the presence of a size variance of quantum dots in the real heterointerface. The modeled distribution of the dark current-voltage characteristic at 90 K and zero shift reveals the value of the dark current density of 10-7 A/cm2, which is an order of magnitude less than the measurement results (10-6 A/cm2). The difference in the pattern of dependence distribution at negative and positive bias associated with the presence of quantum dots of larger size is observed.
关键词： quantum dots,InAs/GaAs heterointerfaces,photoluminescence,dark current-voltage characteristics
更新于2025-09-12 10:27:22
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Frequency and energy characteristics of a Cu–Ne laser at different durations of the leading edge of the excitation pulse
摘要： The lasing characteristics of a copper vapour laser in a tube with forced heating, having a length of 50 cm and a diameter of 2 cm, excited by a train of pulses are investigated. Comparative studies of the frequency and energy characteristics of the laser are performed with a leading edge duration of the excitation pulse of ~25 ns (when the capacitance discharges through a thyratron and a magnetic compression line) and ~3 and 1 ns (using circuits with a high-speed switch – kivotron). It is shown that a decrease in the leading edge duration gives rise to an increase in the optimal pulse repetition rate up to ~30 kHz, the generation efficiency up to 3.2 % and the generation power per unit length over 100 W m–1. The results obtained confirm the concept of limiting the frequency and energy characteristics of a copper vapour laser due to the insufficient rate of energy input into the plasma at high prepulse electron concentrations.
关键词： duration of the excitation pulse leading edge,frequency and energy characteristics,copper vapour laser
更新于2025-09-12 10:27:22
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Implementation of slow wave characteristics in a microstrip antenna and its implementation with substrate integrated waveguide
摘要： In this article, a planar slow wave long-wire-antenna (LWA) is proposed for RF and microwave applications. Mathematical design equations of transformation of cylindrical LWA into planar microstrip antenna are presented. Slow wave effect produced by LWA is demonstrated in terms of group delay in a square slot aperture antenna and the same is compared with the proposed LWA embedded with square slot in the ground plane. Furthermore, substrate integrated waveguide is embedded with the proposed structure which further enhance the antenna gain and group delay. Group delay of about 2 ns is enhanced to the value of 26.7 ns after the integration of substrate integrated waveguide with LWA. Finite element method is used to investigate the design through Ansoft HFSS simulator, which is further validated by measured results of fabricated prototype.
关键词： slow wave characteristics,substrate integrated waveguide,cross-polarization suppression,defected ground structure,long wire antenna
更新于2025-09-12 10:27:22
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Realtime monitoring on the HIT photovoltaic module characteristic parameters at STC, high and low irradiance conditions in Algeria
摘要： This paper deals with the study on 233 Wp HIT PV module characteristics that defines its performance and operation. The chosen HIT PV module is exposed to outdoor conditions at Saida City of Algeria. The module is tested in high irradiance and low irradiance situations that were recorded over a specific year. Based on the monitored data in these two situations, its performance characteristics were evaluated and compared with standard test condition parameters. From the results it is observed that, irradiance variation effects the HIT PV module characteristics. The variation in maximum power extracted, efficiency, and fill factor were observed. Apart from this weather parameters like ambient temperature, module temperature, wind speed, and relative humidity had also influenced the performance characteristics of HIT PV module.
关键词： fill factor,HIT PV module,PV monitoring,outdoor characteristics,Photovoltaics,PV efficiency,high, low and STC irradiance
更新于2025-09-12 10:27:22
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Recent Developments in Photovoltaic Materials and Devices || Experimental Study of Current-Voltage Characteristics for Fixed and Solar Tracking Photovoltaics Systems
摘要： The efficiency of solar electric systems basically depends on the materials used in making the solar cells and regardless of the type of application: fixed or tracking photovoltaics (PV), the quality and quantity of power produced by PV systems depend on both the amount of solar radiation incident on the solar panels as well as the current and voltage characteristics of the load. This present work, which involves field installation of a fixed PV alongside an existing equivalent tracking PV, simultaneously monitored the current and voltage response of both systems to changing solar radiation and ambient temperatures. The comparative results of the study provide a framework for decision-making on the choice of either of the systems and have shown that in the UK, both systems have a relatively slow electrical response to sunrise while the performance of fixed PV systems approximates that of tracking PV systems at noon time.
关键词： voltage-current (I-V) characteristics,solar radiation,maximum power,fixed PV,solar tracking PV
更新于2025-09-12 10:27:22
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Femtosecond laser pulse ablation characteristics of polymer-derived SiAlCN ceramics
摘要： Polymer-derived ceramics (PDCs) are promising high-performance materials for various applications, yet their brittleness represents major drawback in their machining. Femtosecond laser pulse ablation is non-contact rapid processing method used in precision machining of PDCs. Herein, two laser parameters (laser energy fluence and rotational speed) were investigated to achieve laser–material interactions and machining characteristics via machine single circular lines, blind holes, and through-holes in polymer-derived SiAlCN ceramics. With the decrease in rotational speed, the morphology of single circular lines gradually roughened and heat-affected zone was produced. Varying ablation rates were obtained at different energy fluences. For blind holes, three different ablation regions were observed. As the energy fluence increased, blind holes gradually transformed into through-holes. Through-holes with near-cylindrical profiles and minimal collateral damage were obtained. Ablation debris deposited around through-holes were indicative of N release, breaking of Si-N and C-C bonds, and formation of SiOx. Laser ablation of PDCs led to the formation of laser-induced surface structures, bubble pits, stripe structures, molten materials, and sphere-like particles.
关键词： femtosecond laser pulse,ablation characteristics,polymer-derived ceramics,energy fluence
更新于2025-09-12 10:27:22
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Enhanced Photoresponse of Indium-Doped Tin Disulfide Nanosheets
摘要： Doping of tin disulfide (SnS2) is an effective strategy to regulate its physical and chemical properties. In this work, In doping was used to manipulate the photoresponse behavior of SnS2-based photodetectors. In-doped SnS2 nanosheets were synthesized via a facile hydrothermal method. It was found that the In doping concentration plays an important role in the size of the fabricated SnS2 nanosheets. With the increase in the In doping concentration, the lateral size of samples increased from ~210 to ~420 nm, but the crystallinity became poor at higher concentrations. EDX-mapping results show that the In was homogeneously distributed in the samples. In addition, a redshift was observed in the binding energy of Sn and S with the increased In doping concentration, which may be due to the p-type doping of In in SnS2. After In doping, the performance of SnS2-based photodetectors was significantly improved. The photoresponse speed of In-doped SnS2-based photodetectors was faster than pristine SnS2-based devices under the illumination of 532 and 405-nm lasers. This work develops an effective approach of In doping to enhance the photoresponse characteristics of SnS2-based photodetectors, and proves that In-doped SnS2 has vast potential in optoelectronic applications.
关键词： photoresponse characteristics,Doping,Tin disulfide,photodetector,Layered metal dichalcogenides
更新于2025-09-12 10:27:22
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Efficient and Stable FASnI <sub/>3</sub> Perovskite Solar Cells with Effective Interface Modulation by Low‐Dimensional Perovskite Layer
摘要： Many factors have been demonstrated as having an influencing effect on the osteogenic activity of the peptide-modified bone repair materials. However, most of studies only focus on one or two aspects that result in an incomplete direction for materials preparation, characterization, and performance evaluation. In this review, we reported several factors through summarizing previous research studies, which are mainly centered on three aspects: (1) the characteristics of peptide immobilized on the surface of matrix (e.g., type and length of sequence, structure, and density); (2) the combination mode between peptide and matrix (including covalent binding in selective or nonselective immobilization, and noncovalent binding through simple absorption or mixing with the matrix, and other factors in covalent binding); and (3) the properties of the matrix (including surface structure and morphology, dimension, mechanical properties, hydrophobic–hydrophilic balance, adsorbing proteins on materials), and the other possible influencing factors such as binding to other peptides. In addition, attentions were paid to the introduction and the discussion of newest studies and the analysis of mechanism.
关键词： peptide-modified bone repair material,osteogenic activity,combination modes between peptide and matrix,properties of matrix,characteristics of peptide
更新于2025-09-11 14:15:04
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Orthorhombic WP co-catalyst coupled with electron transfer bridge UiO-66 for efficient visible-light-driven H2 evolution
摘要： The abundant transition metal phosphides co-catalysts on the earth can satisfy the sustainable and clean solar H2 production through photocatalytic water splitting, which is promising to replace the rare precious metals, such as Pt, Au, Pd, Ru and so on. In this paper, we use the temperature-programmed solid phase method to prepare WP nanoparticles. Based on the Density Functional Theory (DFT) calculations, we demonstrate that the WP nanoparticles possess outstanding electrical conductivity and excellent capability to transport electrons. WP nanoparticles are loaded onto the surface of UiO-66 via the ultrasound-assisted impregnation method to induce a highly efficient visible-light photocatalytic H2 production activity of 384 mmol in 5 h, which is 10.67 times than that of pure UiO-66. The catalytic performance is attributed to the excellent metallic conductivity and the favourable Fermi level position of WP nanoparticles. Further studies of PL, TRPL and Mott-Schottky curves, we can not only know that the modification of WP nanoparticles do improve the electron transfer ability, but also that the matched work functions between the EY and UiO-66 provides a feasible thermodynamic path for the transmission of electrons. Our work demonstrates that the earth-abundant transition metal phosphides material have the potential to construct cheaper and high catalytic performance photocatalysts.
关键词： WP,DFT calculations,H2 production,UiO-66,Metallic characteristics
更新于2025-09-11 14:15:04
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Characteristics analysis of the photovoltaic thermal heat pump system on refrigeration mode: An experimental investigation
摘要： Photovoltaic thermal heat pump technology stands for the combination of solar heat pump technology and a photovoltaic system, which has the characteristics of tri-generation (heating, cooling, and electricity) to meet the building's energy requirement. In this paper, the dual-use photovoltaic thermal heat pump system was used and investigated experimentally with an emphasis on the refrigeration mode, which with the feature of the novel roll-bond photovoltaic thermal unit working as condenser directly. Moreover, renewable energy such as solar radiation and long-wave radiation are the main energy source of this system. The experimental investigation of the system comprising; 4 roll-bond photovoltaic thermal units, 1 horsepower heat pump unit and 600 L ice storage tank was carried out. The performance evaluation method and uncertainty analysis of the system was proposed and implemented along with the examination on the refrigeration performance and operating characteristics of the system. The results indicate that the proposed photovoltaic thermal heat pump system can achieve the refrigeration for building space cooling demand in summer with high performance and long-term stable operation. This study could provide a valuable reference for the photovoltaic thermal heat pump multi-generation system design and large-scale practical application in northern China.
关键词： Photovoltaic thermal heat pump,Experimental study,Refrigeration performance,PVT,Operation characteristics
更新于2025-09-11 14:15:04