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Effect of Nd doping on structural and opto-electronic properties of CdO thin films fabricated by a perfume atomizer spray method
摘要： A perfume atomizer-assisted spray pyrolysis method was employed to fabricate undoped and neodymium (Nd)-doped cadmium oxide (CdO) thin films. X-ray diffraction results reveal that all the films are polycrystalline with a cubic structure with a preferential orientation along the (200) direction. Scherrer’s formula was used to calculate the crystallite size of Nd-doped CdO films. Energy dispersive spectroscopy results show that Cd, Nd and O elements are present in Nd-doped CdO thin films. The optical absorption of the doped films is increased along with increasing Nd-doping level. The prepared CdO thin films have a high absorption coefficient in the visible region and the optical band gap is decreased on increasing Nd doping content. The electrical carrier concentration (n) of the deposited films is increased with increasing Nd doping concentration. Photoconductivity studies of a nanostructured Al/Nd–n-CdO/p-Si/Al device showed a non-linear electric characteristics indicating diode-like behaviour. Prepared Nd:CdO films could increase the photo-sensing effect of this n-CdO/p-Si heterostructure. These Nd-doped CdO thin films may open a new avenue for photodiode application in near future.
关键词： optical and electrical properties,Nd:CdO,thin films,spray using perfume atomizer
更新于2025-09-23 15:23:52
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Conjugate Electrospinning Construction of Microyarns with Synchronous Color-Tuned Photoluminescence and Tunable Electrical Conductivity
摘要： Here, we report a strategy for constructing {[Tb(BA)3phen + Eu(BA)3phen]/PAN}//[PANI/PAN] (BA = benzoic acid, phen = phenanthroline, PANI = polyaniline, PAN = polyacrylonitrile) hetero-structured microyarns simultaneously endowed with the bi-functionality of tunable luminescence colors and electrical conductivity by using a conjugate electrospinning technique. The obtained hetero-structured microyarns are composed of [Tb(BA)3phen + Eu(BA)3phen]/PAN luminescent nano?bers and PANI/PAN electrically conductive nano?bers, realizing ef?cient separation of dark-colored PANI from rare earth (RE) complexes, and thus the enhanced luminescent performance is obtained. Under 276-nm ultraviolet light excitation, the emitting light color of the hetero-structured microyarns can be adjusted in a broad range of green–yellow–red by changing the proportion of RE complexes. The electrical conductivity of the hetero-structured microyarns also can be modulated via tuning the percentages of PANI. These hetero-structured microyarns, by virtue of their luminescent properties and electrical performance, are expected to be applied in multifunctional applications.
关键词： photoluminescence,conjugate electrospinning,Microyarn,electrical properties
更新于2025-09-23 15:23:52
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Effect of structures and substrate temperatures on BaZn0.06Bi0.94O3- perovskite-based NTC thermistor thin films
摘要： Negative temperature coefficient (NTC) thermistor thin films based on perovskite-type BaBiO3 (BB) and BaZn0.06Bi0.94O3-δ (BZB) were successfully prepared by radio frequency (RF) magnetron sputtering method on Pt substrate. The crystal structure and grain morphology of the BZB and BB films deposited at different substrate temperatures (25–200 °C and 200 °C, respectively) were examined by X-ray diffraction (XRD) and atomic force microscope (AFM). The substrate temperature had a significant influence on the crystallinity and phase structure, in which the main crystalline phases with the cubic and tetragonal BaBiO3-based perovskite structures could be obtained on the substrate temperatures of 100 °C and 200 °C, respectively. On the other hand, the electrical properties were analyzed by measuring the resistance temperature (ρ-T) characteristics, and all the thin films exhibited good NTC thermistor characteristics. In addition, the grain (Rg) and grain boundary (Rgb) contribution to the total resistance were estimated by three parallel R-CPE equivalent circuits in series, in which the main contribution of resistance for BZB thin film deposited at 200 °C was derived from Rg response rather than that in Rgb at the higher temperature range. This was one of the most important reasons why this sample had a good NTC behavior, and this result was confirmed by the current-voltage (I-V) characteristics analysis. For the BB film, the room-temperature resistivity (ρ25) was 1540 Ω cm (B25/85 –3240 K), while the ρ25 value decreased to approximately 1156 Ω cm (B25/85 –3183 K) for BZB film deposited at a same substrate temperature (200 °C). This is mainly due to the change in crystal structural characteristics. It is believed that the substitution of Zn2+ for BB thin films deposited at an appropriate temperature will be useful for low-resistance applications as novel thin film NTC thermistors.
关键词： Substrate temperature,NTC thermistor,Electrical properties,BaBiO3,Thin film
更新于2025-09-23 15:23:52
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Combustion synthesis of nontoxic water-induced InYO thin film and application in thin film transistor
摘要： In the work, novel indium yttrium oxide (InYO) thin ?lms are prepared by an environmentally friendly aqueous solution process. Y element is added to suppress the generation of oxygen vacancies. The e?ect of Y doping on the performance and stability of nontoxic water-induced InYO thin ?lm transistors (TFTs) is ?rstly examined. With the increase of Y doping contents, o?-state current is decreased and mobility decreases from 15.8 to 11.7 cm2 V?1 s?1. Furthermore, the stability under positive bias stress is also obviously improved. The device with 2 mol% Y element shows an optimized electrical performance and good stability, including mobility of 12.8 cm2/V s, threshold voltage of 1.4 V, subthreshold swing of 0.33 V/decade and threshold voltage shift of 2.31 V under positive voltage stress of 5 V for 10,000 s. The performance improvement is attributed to the decrease of oxygen vacancies and the decline of interface trap density by Y addition.
关键词： Thin ?lms,Amorphous materials,Electrical properties,Sol-gel chemistry
更新于2025-09-23 15:23:52
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Electrode Dependence of Local Electrical Properties of Chemical-Solution-Deposition-Derived BiFeO <sub/>3</sub> Thin Films
摘要： The nanoscale electrical properties of chemical solution deposition(CSD)-derived BiFeO3 grown on pulsed laser ablated La0.67Sr0.33MnO3//SrTiO3 (001) thin film heterostructures are investigated using a host of scanning probe microscopy techniques, including electrostatic force microscopy(EFM), scanning Kelvin probe microscopy(SKPM), piezoresponse force microscopy (PFM), and conductive AFM(CAFM). EFM and SKPM confirm the p-type nature of the CSD derived BFO thin films as well as charge accumulation at the film surface after electrical bias. For BiFeO3 films of a fixed thickness (~35 nm), the local current-voltage (I-V) behavior obtained by CAFM is strongly dependent on the La0.67Sr0.33MnO3 bottom electrode thickness. BiFeO3 films on a 20 nm thick La0.67Sr0.33MnO3 demonstrate the typical switchable diode behavior governed by polarization orientation. However, when the thickness of La0.67Sr0.33MnO3 is reduced to less than 5 nm, the BiFeO3 films show only forward diode behaviors regardless of polarization orientation, when the applied bias is up to ±4 V. Higher sweep bias (i.e. ±8V) breaks down the diode, following which the BiFeO3 film shows strong resistive switching. The interface band structure for the ultra-thin LSMO case, which is very sensitive to accumulation/depletion of carriers at the BFO-LSMO interface, is suggested as the trigger for this resistive switching.
关键词： chemical solution deposition,ferroelectric,electrical properties,ultrathin lanthanum strontium manganite,p-type bismuth ferrite thin films
更新于2025-09-23 15:23:52
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Interfacial passivation of n-ZnO/p-Si heterojunction by CuI thin layer
摘要： The ZnO/Si heterojunction diode can be integrated with the Si process, which has attracted great attention in recent years. However, the large number of interface states at the ZnO/Si heterojunction interface could adversely affect its optoelectronic properties. Here, n-type ZnO thin film was deposited on p-Si substrate for formation of an n-ZnO/p-Si heterojunction substrate. To passivate the ZnO/Si interface, a thin CuI film interface passivation layer was inserted at the ZnO/p-Si heterojunction interface. Electrical characterization such as I–V and C–V characteristic curves confirmed the significant improvement of the heterojunction properties e.g. enhancement of forward current injection, reduction of reverse current and improvement of the rectification ratio. These results showed that the passivation of interface is critical for ZnO/Si heterojunctions.
关键词： CuI,heterojunction,interface states,electrical properties,ZnO/p-Si
更新于2025-09-23 15:23:52
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<sup>125</sup> Te nuclear magnetic resonance and impedance spectroscopy study of topological insulator Bi <sub/>2</sub> Te <sub/>3</sub> nanoparticles mixed with insulating Al <sub/>2</sub> O <sub/>3</sub> nanoparticles
摘要： We have studied topological insulator Bi2Te3 nanoparticles mixed with insulating Al2O3 nanoparticles by means of 125Te nuclear magnetic resonance (NMR) and impedance spectroscopy. Our 125Te NMR lineshape measurements revealed the Knight shift of a satellite peak that increased with the mixing ratio of the Al2O3 nanoparticles, indicating that the mixing increases the surface-to-volume ratio of the Bi2Te3 nanoparticles. It is also shown that the impedance spectroscopy can be employed as a simple and effective means of distinguishing the surface electrical properties of the topological insulators in general.
关键词： surface electrical properties,topological insulator Bi2Te3 nanoparticles,125Te nuclear magnetic resonance,impedance spectroscopy
更新于2025-09-23 15:23:52
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Disorder Control in Crystalline GeSb <sub/>2</sub> Te <sub/>4</sub> and its Impact on Characteristic Length Scales
摘要： Crystalline GeSb2Te4 (GST) is a remarkable material, as it allows to continuously tune the electrical resistance by orders of magnitude without involving a structural phase transition or stoichiometric changes. While well-ordered specimen are metallic, increasing amounts of disorder eventually lead to an insulating state with vanishing conductivity in the 0 K limit, but a similar number of charge carriers. Hence, GST provides ideal grounds to explore the impact of disorder on transport properties. Here, a sputter-deposition process is employed that enables growing biaxially textured GST films with large grain sizes on mica substrates. The resulting films exhibit a systematic variation between metallic and truly insulating specimen upon varying deposition temperature. Transport measurements reveal that their electron mean free path can be altered by a factor of 20, while always remaining more than an order of magnitude smaller than the lateral grain size. This proves unequivocally that grain boundaries play a negligible role for electron scattering, while intra-grain scattering, presumably by disordered vacancies, dominates. These findings underline that the insulating state and the system’s evolution toward metallic conductivity are intrinsic properties of the material.
关键词： metal–insulator transition,electrical properties,phase-change materials,disorder,structural properties
更新于2025-09-23 15:22:29
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</sub> ) Interlayer
摘要： Electrical and dielectric properties of Au/n-Si metal–semiconductor structures with high dielectric have been examined by capacitance/conductance–voltage (C/G–V) measurements in the frequency range of 5–500 kHz at room temperature. Voltage-dependent profiles of interface states (Nss) and resistance (Ri) were extracted from the C and G data using the low–high-frequency capacitance and Nicollian–Brews methods, respectively. The real and imaginary components of the complex dielectric constant (ε', ε''), electric modulus (M', M''), and ac conductivity (σac) were calculated from the C and G data. All parameters have a strong relation with frequency and voltage, especially at low frequencies due to Maxwell–Wagner relaxation and Nss. The observed peaks in the Nss–V and Ri–V plots can be ascribed by the special distribution of Nss at M/S interface. These results confirmed that [2% graphene cobalt-doped (Ca3Co4Ga0.001Ox)] interlayer has high-dielectric constant and can be used an interlayer instead of the traditional SiO2 at M/S interface to increase their capacitance or more charges/energy storage and reduce both the values of Nss and series resistance (Rs). The values of σ are almost constant at lower–intermediate frequencies, but they start to increase at high frequencies that are corresponding to the dc and ac conductivity, respectively.
关键词： electrical properties,nanostructures,Dielectric properties,graphene,polymer
更新于2025-09-23 15:22:29
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Effects of low-temperature sintering on surface morphology and electrical performance of silver nanoparticle/carbon nanotube composite films
摘要： Silver nanoparticle (AgNP)/carbon nanotube (CNT) composites are drawing increasing attention for several applications, especially where transparency is required. However, interfacial interaction and stability of the AgNP/CNT composites have been scarcely investigated. In the present study, transparent coatings were prepared from dispersed AgNP-coated multiwalled CNTs and exposed to different annealing conditions. The changes in surface morphology and evolution of interfacial configuration of AgNP-decorated CNT transparent composite films were investigated. Under certain conditions, CNT ropes were glued to one another by the melted AgNP aggregates, resulting in the improvement of the measured electrical properties. The in situ measurements of the electrical properties allowed correlating the AgNPs sintering mechanism with the morphological observations. Notably, at a given temperature, increasing the initial film density increased the time necessary to complete the AgNPs sintering. The obtained results show that the electrical resistance can be used as a tool to indirectly monitor the network state of transparent AgNP-decorated CNT composite films, hence paving the way to tuning the composite film properties with a high precision for the desired application. These findings also explain the mechanism of reinforcement of polymer nanocomposites by the current nanofillers.
关键词： A. Silver nanoparticle,B. Carbon nanotube,E. In situ monitoring,D. Sintering,F. Electrical properties,C. Nanocomposite
更新于2025-09-23 15:22:29