•Study Objective: Investigate the impact of varying DIO thickness on the OPV system.•Methodology: Simulation for impedance data, validating electrical modulus choice, and determining relaxation ...times.•Data Analysis: The deconvolution approach highlights relaxation processes, offering a powerful method for assessing BHJ morphology.•Interface Stability: Despite increased active layer thickness, PEDOT: PSS/PBDTTT-C: PC70BM and PBDTTT-C: PC70BM/Ca interfaces maintain constant conductivity values.•Conclusions: The approach proves powerful for analyzing additive impact in solar cell active layers.
Impedance and dielectric spectroscopy is a well-known technique for characterizing interfaces, especially donor/receiver interfaces in bulk heterojunction (BHJ) solar cells. This technique was employed to investigate the interface of poly (4,8-bis-alkyloxybenzo(1,2-b:4,5-b0) dithio-phene-2,6-diyl-alt- (alkyl thieno (3,4-b) thiophene-2-carboxylate)-2,6-diyl) (PBDTTT-C): PC70BM in bulk heterojunction with DIO as additive. For this reason, a simulation was carried out to generate the complex impedance, modulus, and complex conductivity data based on the electrical parameters extracted from the equivalent circuit. Therefore, a new approach based on the coupling of complex functions such as impedance, modulus, and conductivity has been proposed. In addition, an extrapolation and deconvolution approaches are used to highlight the relaxation processes, the BHJ layer process, the two electrical contacts of the interfaces between PEDOT: PSS/PBDTTT-C: PC70BM and PBDTTT-C: PC70BM/Ca process, and the electrode polarization process. In the next step, the remove the low-frequency process enhances the visibility of other processes, particularly observable in the evolution of the electrical modulus and the conduction parameters associated with each process. In the complex functions, there was a good correlation between all parameters derived from both processes. The characteristics of the conduction processes, such as conductivity values at low and high frequencies and ionic strength were then extracted. All these parameters were evaluated and discussed as a function of the thickness of the active layer. Finally, we demonstrate that the electrical modulus and complex conductivity can be perfect tools to characterize the donor/acceptor interfaces.
The cadmium sulfide (CdS) nanopowders have been prepared by ball-milling method, and CdS-polyvinyl alcohol (PVA) nanocompound in the form of film has been deposited on a p-Si wafer as an interfacial ...layer by spin-coating method. The impedance characteristics of the fabricated Al/CdS-PVA/ p-Si (metal-polymer-semiconductor)-type structures were studied in the frequency and voltage range of 5 kHz-5 MHz and ±1 V, respectively, by considering interface states (D it ), series resistance (R s ), and interfacial layer effects at 300 K. While the voltage and frequency dependence profiles of D it were evaluated from the low-high frequency capacitance (C LF -C HF ) and Hill-Coleman methods, R s profiles were evaluated from the Nicollian and Brews method. Doping concentration atoms (N A ) and barrier height Φ B (capacitance-voltage (C-V)) values were also obtained from the reverse bias C-2 versus V plots for each frequency. While D it and R s values decrease with increasing frequency almost exponentially, Φ B (C-V) increases linearly. Therefore, both the measured capacitance (C m ) and conductance (G m /w) values were corrected to eliminate the R s effect. The experimental results show that R s value is more effective on the impedance measurements at high frequencies in the accumulation region, but D it is effective at low frequencies in the depletion region.
The present study investigated the influences of water ingress on the electrical resistivity and electromechanical sensing responses of CNT/cement composites. The water absorption, mechanical, ...electrical, and electromechanical sensing characteristics of the composites were assessed in terms of water absorption rate, compressive strength, electrical resistivity, tunneling-induced electrical resistivity, fractional change in the resistivity (FCR), and R-squared value. The water absorption rate increased, and compressive strength decreased as the CNT content and water-to-cement ratios increased. These were ascribed to an addition of the dispersion agent and water which caused microstructures of the composites more porous. In addition, the tunneling-induced electrical resistivity test exhibited that the tunneling effects became more pronounced with increase of the CNT and water contents. In electromechanical sensing test, FCR value reached the highest level at CNT content 0.2%, and R-squared value enhanced as water ingress was reduced. In this regard, it can be concluded that the new types of materials with high hydrophobicity are necessary to improve the stability of the electrical electromechanical sensing capability of the CNT-based cementitious sensors as exposed to the water conditions.
•The tunneling effect was enhanced with CNT and water contents.•The sensing characteristics were the most pronounced at CNT content 0.2%.•The sensing repeatability was enhanced as water ingress was reduced.
Gold (Au) thin films were deposited over the HgCdTe (mercury cadmium telluride) surface by a thermal-evaporation deposition technique. The thermally grown Au films were investigated using different ...characterization techniques, X-ray diffraction (XRD), energy dispersive X-ray (EDX) analysis, atomic force microscopy (AFM), scanning electron microscopy (SEM), and current-voltage (I–V)/resistance measurement. The maximum film growth occurs along with the preferred orientation (111). The grown Au film possesses a cubic fcc structure, desired elemental compositions, and purity. The AFM confirms that the films were uniform, dense, and had very low roughness. The films attained the desired grain size of film-forming particles. The optimized Au films were established and further employed to fabricate the transfer length method (TLM) structure with configuration (Au/p-HgCdTe). The I–V and resistance measurements of the as-deposited TLM structure produced the Ohmic Au-contact with low specific contact resistance (ρc) of 2.73 × 10−3 Ω cm2. Annealing treatment (contacts annealed for 2 h at 80 °C in the air) was applied to the as-deposited TLM structure and the measured value of specific contact resistance (ρc) for the annealed Au contact (Ohmic behaviour) is 7.11 × 10−4 Ω cm2 that is relatively low than the as-deposited contacts. Thermal annealing has reduced the magnitude of ρc by about one order. TLM structures (as-deposited and annealed) exposed the efficiency of Au thin films as an effective Ohmic contact. Thus, Au thin films could be used to create a compelling and appropriate Ohmic p-contact to fabricate HgCdTe infrared detectors.
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•Gold (Au) thin films were fabricated on HgCdTe substrate with a thermal-evaporation technique for Ohmic contact formation.•Au film originated with an excellent and desired surface morphology and purity.•Thermal annealing improved the magnitude of specific contact resistance by about one order.•TLM structures (as-deposited/annealed) exposed the efficiency of Au thin films as an effective Ohmic contact.•Au thin film could create a compelling and appropriate Ohmic p-contact to fabricate HgCdTe IR detectors.
In this study, we evaluated the changes of the properties of TiO2 thin films conducted to O2 plasma treatment at various plasma powers. The XPS analysis showed that the concentration of oxygen ...vacancies in the TiO2 thin films was reduced by the O2 plasma treatment. In the GIXRD analysis, it was confirmed that as the O2 plasma treatment progressed, the anatase peak intensity of TiO2 increased and a new anatase peak was detected. In addition, according to HR-TEM analysis the crystallinity became excellent. The AFM analysis showed that the roughness of the as-deposited TiO2 thin film and O2 plasma-treated TiO2 thin film were almost the same. The I–V analysis showed that the leakage current density of the 800 W O2 plasma-treated TiO2 thin film (∼10−4A/cm2) was 100 times lower than that of the as-deposited TiO2 thin film (∼10−2A/cm2). The dielectric constant of the O2 plasma-treated TiO2 thin films was approximately 24–25, which is higher than that of the as-deposited TiO2 thin film (k∼17) because of the anatase structure.
In this article, the effects of active Ag electrodes on the <inline-formula> <tex-math notation="LaTeX">{R}_{ \mathrm{\scriptscriptstyle OFF}}/{R}_{ \mathrm{\scriptscriptstyle ON}} ...</tex-math></inline-formula> ratio, SET/RESET voltages, and endurance characteristics of a sol-gel TiO x resistive memory are investigated. Stable bipolar resistive switching (RS) behavior with a large <inline-formula> <tex-math notation="LaTeX">{R}_{ \mathrm{\scriptscriptstyle OFF}}/{R}_{ \mathrm{\scriptscriptstyle ON}} </tex-math></inline-formula> ratio of 10 5 is observed in an Ag/TiO x /n + -Si resistive memory. The SET and RESET processes can only be triggered by positive and negative voltages, respectively. Nonpolar RS behavior is found when directly using a tungsten probe to measure the <inline-formula> <tex-math notation="LaTeX">{I} </tex-math></inline-formula>-<inline-formula> <tex-math notation="LaTeX">{V} </tex-math></inline-formula> curves of a TiO x /n + -Si device. A high voltage of ~±40 V is needed to induce the SET process. In addition, the RS behavior is not stable and can only repeat few times. When the top and bottom electrodes are both Ag (Ag/TiO x /Ag), the SET process can be easily triggered by a low voltage regardless of the voltage polarity. However, the RESET process does not happen in the following voltage cycles. Dramatic differences in the RS characteristics of these devices verify the impact of the Ag electrode on the RS characteristics of the sol-gel TiO x layer.
In this work, by altering oxygen partial pressure (OPP) and sputtering power (<inline-formula> <tex-math notation="LaTeX">{P}_{\text {RF}} </tex-math></inline-formula>) of the radio frequency (RF) ...magnetron sputtering process, we investigate electrical evolution of the p-type SnOx film and transistor. Herein, combining device current-voltage (such as ON-state current and field-effect mobility), low-frequency noise (LFN), and gate-bias-stress characteristics, we find that the optimal OPP range is 4.8%-7.2% for the SnOx film deposition at <inline-formula> <tex-math notation="LaTeX">{P}_{\text {RF}} </tex-math></inline-formula> of 70 and 30 W. Based on X-ray photoelectron spectroscopy (XPS), the SnOx films deposited at high power (70 W) show less sensitivity to OPP, which leads to the slow transition of internal Sn2+, Sn4+ states, and a relatively large process window. Furthermore, the defect states inside the SnOx are analyzed. The oxygen interstitials (Oi), as deep acceptors, keep inactive regardless of the external bias. The oxygen vacancies (Vo) and the ionized Vo2+ states, which act as the electron traps, get suppressed and are attributed to the ambipolar behavior in the SnOx transistor, while increasing the OPP. This work benefit lies in a comprehensive analysis of the sputtering process parameters impact on SnOx film and transistor properties and their underlying defects.
The effects of insulative, semi-conductive and conductive nanostructured particles at various concentrations on critical parameters of Nano-Liquid Insulation (NLI) systems are experimentally ...investigated and the results are discussed in detail. In this study, liquid insulations such as Sunflower Oil (SO) and Rapeseed Oil (RO) as Natural Esters and conventional Mineral Oil (MO) as petroleum derived oil have been utilized as base fluid. Here, various nanostructured Magnetite (Fe3O4) as conductive nanoparticle, Zinc Oxide (ZnO) as semi-conductive nanoparticle and Silica (SiO2) as insulating nanoparticle are employed to investigate the influence of concentration and different types of nanoparticles in critical characteristics of base fluids. Experimental findings reveal that, the concentration and the types of nanoparticles make an impact in the performance of NLIs. The conductive nanoparticles based NLIs with higher concentration offer higher enhancement in performance characteristics compared to semi-conductive and insulating nanoparticles based NLIs.
•Mineral oil and natural esters are used as base fluids.•Nanofluids are prepared using different nanoparticles at various concentrations.•Effects of nanoparticles on liquid insulations are experimentally analyzed.•Dielectric properties of the NLIs are enhanced due to slow moving electrons.•Fe3O4 nanoparticle dispersed liquid insulations performed better than others.
•The design of an irradiation capsule has been developed to study the electrical characteristics of cables with mineral insulation.•The capsule provides an irradiation temperature of 500 °C and a ...fast neutron fluence of 1021 cm−2.•Calculated data on the gradient of neutron flux and temperature along the height of the capsule are provided.•The number of defects arising after reaching the target fluence of fast neutrons was estimated.
At the WWR-K reactor, studies were started on the radiation resistance of signal cables with two types of mineral insulation (MgO and Al2O3). It is planned to accumulate fluence of fast neutrons ∼ 1020 cm−2 in cables. The irradiation temperature will be 500 ± 50 °C. The in-situ study of the degradation of the electrical properties of the insulation of signal cables will be carried out. This paper presents a capsule design, the results of complex calculations for the development of the capsule design, the expected neutron fluences, the dpa in steel, the technique for in-reactor measurement of electrical characteristics, and a work plan for the further studies. It is shown that the developed capsule forms the necessary conditions for irradiation. In particular, the temperature control range is 400–600 °C. The cable irradiation time until the target neutron fluence is reached will be about 100 effective days.
