Field Emission Secondary Electron Microscopy Research Articles

A novel mesoporous CoMn2O4@rGO composite as an electrode material for hybrid supercapacitor for energy storage device applications

Cobalt‑manganese spinel oxide (CoMn2O4) was hybridized with reduced graphene oxide (rGO) via a facile hydrothermal process and a highly porous three-dimensional (3D) structure was constructed. The phase structure, chemical bands, morphology and chemical state of the synthesized powders were investigated by X-ray diffraction (XRD), Raman spectroscopy, field emission secondary electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). CoMn2O4@rGO electrode delivered high specific capacitance of 1578 Cg−1at 1 Ag−1 in 1.0 M KOH electrolyte and an outstanding cycling stability with 94.2 % retention over 5000 cycles, suggesting the great potential application of this material in advanced energy storage device. The rGO makes great contributions to hybrid through supplying a conductive support for CoMn2O4, resulting in the prominent specific capacitances and outstanding cycle stability. Besides, the assembled CoMn2O4@rGO//AC asymmetric supercapacitor (ASC) displays the maximum energy density of 35.6 Whkg−1 at a power density of 8916.9 Wkg−1. Significantly, an ultralong cycling life of 98.2 % capacitance retention is achieved for the ASC device after 10,000 charge/discharge cycles at 1 Ag−1.

The recrystallization, texture and mechanical behavior of hot rolled and annealed Mg-10Ho binary alloy

The recrystallization, texture, and mechanical properties of hot-rolled and hot-rolled + annealed Mg-10Ho (wt %) are investigated. Mg-10Ho binary alloy is first solution treated followed by multipass rolling at 420 °C for up to 50 % reduction and subsequently annealed at 400 °C for different times for up to 60 min. The microstructure of deformed and annealed samples was characterized using a field-emission secondary electron microscope (FESEM) and electron back-scattered diffraction (EBSD) and the mechanical properties were examined using hardness and tensile tests. The as-rolled microstructure contains fine dynamic recrystallized grains and different types of deformation twins. With increasing annealing time, a decrease in the hardness was observed, suggesting initiation of recovery and static recrystallization. After 10 min of annealing, an equiaxed, nearly fully recrystallized microstructure with a grain size of 14 µm and weaker basal texture was obtained. This annealed sample exhibits an ultimate tensile strength of 213 MPa, yield strength of 145 MPa, and ductility of ∼7 %. Such an optimum combination of strength and ductility is attributed to the combined effect of solid solution strengthening, grain refinement, and texture weakening. Additionally, the Johnson-Mehl-Avrami-Kolmogorov (JMAK) model was used to understand the recrystallization kinetics of Mg-10Ho and compared it with that of Mg-10Y. Results indicate that the solute drag effect plays a dominant role in the faster recrystallization kinetics of Mg-10Ho alloy. Finally, the texture variation in Mg-10Ho and Mg-10Y is also explained based on the solute drag effect.

Synthesis and uranium adsorption studies of UiO-66 (Ce) based metal organic frameworks from aqueous solutions

Ce based Metal Organic Framework (MOF) UiO-66 (Ce) and a MOF-composite CeO2@UiO-66 (Ce) were prepared by conventional heating and hydrothermal method respectively. Both the MOFs were characterized using X-ray Diffraction (XRD) technique, Fourier Transform Infra Red (FT-IR) spectroscopy, Field Emission-Secondary Electron Microscopy (FE–SEM), Small Angle X-ray Scattering (SAXS), Thermogravimetric Analysis (TGA), Differential Thermal Analysis (DTA) and Transmission Electron Microscopy (TEM). N2 adsorption-desorption isotherms of UiO-66 (Ce) showed large specific surface area of ∼981 m2/g and a reasonably large pore volume compared to the composite sample. Their uranium adsorption capacity in aqueous solutions was investigated in the pH range 2–6. Uranium adsorption experiments indicated reasonably higher uranium adsorption capacity of 239 mg/g for CeO2@UiO-66 (Ce) compared to UiO-66 (Ce) (190 mg/g). Kinetic studies revealed rapid uranium adsorption in pure MOF compared to the composite material which was attributed to the blocking of pores by CeO2 nanoparticles in the composite material. These frameworks showed good thermal stability as revealed by the thermogravimetric studies. The synthesized MOFs exhibit moderate recyclability using dilute acid and can be utilized in successive cycles. The selectivity studies showed that these MOFs are highly selective to U (VI) compared to Fe (III), Co (II), Ni (II) and Sr (II). This study could pave a way for more advanced material synthesis involving MOFs which could prove very beneficial for the wastewater remediation thus creating a safer environment to live in.

Improvement of corrosion resistance and mechanical properties of chrome plating by diamond-like carbon coating with different silicon-based interlayers

In this study, the silicon-based interlayers for hydrogenated amorphous carbon (a-C:H) coating on a chromium-plated substrate are presented. The a-Si, a-Si:N, a-Si:H and a-SixCy:H interlayers with a thickness of about 306 nm were deposited by direct current magnetron sputtering technique. The a-C:H films with a thickness of about 317 nm was prepared as a top layer by radio frequency-plasma chemical vapor deposition. The a-C:H films with silicon-based interlayers were characterized by x-ray photoelectron spectroscopy, Raman spectroscopy, field emission-secondary electron microscopy, nanoindentation, micro-scratching, and electrochemical corrosion measurements in terms of their structure, morphology, mechanical and adhesive properties, and corrosion resistance. The a-C:H films with an a-Si:H interlayer exhibit the lowest corrosion current density, which is about 36 times lower than that of the uncoated chromium-plated substrate. In addition, the hardness increases from 8.48 GPa for the uncoated substrate to 20.98 GPa for the a-C:H/a-Si:H sample. The mixing with hydrogen gas could reduce the residual oxygen during the deposition process, which could reduce the Si–O bonding and improve the adhesion strength between the a-C:H film and the a-Si:H interlayer and the a-Si:H interlayer and the substrate. Therefore, it can be concluded that the protective a-C:H coating with an a-Si:H interlayer has excellent potential to significantly improve the durability and extend the service life of materials used in abrasive and corrosive environments.

Comparison of the structural and optic al properties of amorphous silicon thin films prepared by direct current, bipolar pulse, and high-power impulse magnetron sputtering methods

This paper presents a comparative study of amorphous silicon (a-Si) thin films deposited by three different techniques: direct current magnetron sputtering (DCMS), bipolar pulse magnetron sputtering (bipolar pulse MS) and high-power impulse magnetron sputtering (HiPIMS). The structurafl properties of the a-Si films with a thickness of ∼112 nm were characterized by X-ray reflectivity and Raman spectroscopy. The surface morphology, optical and mechanical properties of a-Si films with a thickness of ∼400 nm were investigated using a field emission secondary electron microscope, an atomic force microscope, spectroscopic ellipsometry and nanoindentation. It was found that for the same time-averaged discharge power, the deposition rate of the HiPIMS method was lower compared to DCMS and bipolar pulse MS. The a-Si film prepared by HiPIMS method had the lowest root mean square roughness of 0.65 nm and the highest density of 2.21 g/cm3. These results are consistent with the highest refractive index (400–700 nm) of 3.66 and a hardness of 9.09±0.19 GPa in the film, indicating that the HiPIMS method produces denser films than the DCMS and bipolar pulse MS methods. The amorphous silicon thin films fabricated by HiPIMS have the potential to improve the structural and mechanical properties for high performance thin film semiconductor applications.

Investigations on a Fe–Ru–Os–Ir alloy inclusion found in a chromite-bearing ophiolite complex in SE Iran

A nearly euhedral inclusion was observed in an electron microprobe survey focusing on minor minerals in the chromite-bearing ophiolite complex from southeast of Iran. According to properties such as zoning and homogeneity, investigated with a Field Emission Secondary Electron Microscope (FESEM), the inclusion is a homogeneous alloy grain. According to energy-dispersive X-ray (EDX) the grain consists of 41.5–43.0 wt.-% Fe, 28.6 to 31.3 wt.-% Ru, 18.0 to 19.7 wt.-% Os, and 9.1 to 9.5 wt.-% Ir with an average compositional formula of Fe0.422Ru0.298Os0.187Ir0.093. This is the first PGE alloy minerals of such composition found in Iran's ophiolites. Published PGM-bearing alloys of this kind are known as hexaferrum. The aim of the present study is to check the chemistry and zoning of the detected PGM alloy, to discuss its chemical composition and to compare the results with those other hexaferrum occurrences described in literature.

Cu-Doped ZnO Nanoparticles as an Electrochemical Sensing Electrode for Cardiac Biomarker Myoglobin Detection

Cu-doped ZnO nanoparticles were used in the form of a screen-printed electrode on a prefabricated gold-plated electrode for electrochemically determining the concentration of nanomolar myoglobin (Mb), a cardiac biomarker. Initially, Cu-doped ZnO nanoparticles were synthesised through the sol gel method by using three Cu-doping concentrations (varying number of Cu atoms). Then, the synthesised material was analysed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy, and field emission secondary electron microscopy. Analysis revealed a mixed phase of ZnO and CuO, whereas the vibration band in the range of 650-700 cm -1 indicated metal oxide formation. Morphological observation showed uniform-sized spherical particles of approximately 15-20 nm (as nanoparticles) that were evenly distributed, which were also confirmed based on the average particle size estimated using XRD data. The developed electrodes were tested for biomarker concentration from 3 to 15 nM based on cyclic voltammogram and impedance spectroscopic curves, where the redox potential/current/charge transfer resistance changed linearly with Mb and dopant (Cu) concentration. The sensitivity was estimated as 2.13-10.14~μAnM -1 cm -2 with dopant concentration of approximately 0.46 nM as the limit of detection.

Stable high dielectric properties in (Cr, Nb) co-doped SnO2 ceramics

In this research, the microstructure, dielectric, and non-Ohmic properties of (Cr, Nb) co-doped SnO2 ceramics, (Cr0.5, Nb0.5)xSn1-xO2 with x% = 0, 0.5, 1.0, 2.0, 5.0, and 10.0, as a colossal dielectric material and a prospective alternative to co-doped TiO2 ceramics were studied. The X-ray diffraction results indicated that in all compositions, the cassiterite phase was achieved without any secondary phases. Moreover, field-emission secondary electron microscopy showed that the microstructure of samples has different morphologies including typical grains, enlarged grains and prism-like grains microstructure for various sintered samples. The maximum dielectric constant (2737) accompanied by the lowest dielectric loss (0.04) at the frequency of 1 kHz was obtained for (Cr0.5, Nb0.5)0.02Sn0.98O2. The all co-doped SnO2 samples except for x = 10.0 showed non-Ohmic properties. Based on the observed non-Ohmic properties, the mechanism of dielectric properties of (Cr, Nb)-doped SnO2 ceramics was attributed to the internal barrier layer capacitor (IBLC) model. According to this model, samples with higher breakdown electric field demonstrate the better stability of dielectric properties, when DC bias voltage is applied.

Investigation of Mn Doped ZnO Nanoparticles Towards Ascertaining Myocardial Infarction Through an Electrochemical Detection of Myoglobin

Mn-doped ZnO nanostructures were synthesized with three different estimated Mn concentration (atoms/cm 3 ) using sol-gel technique. As synthesized nanostructures were analyzed using X-ray diffraction spectroscopy (XRD), Fourier-transform-infrared spectroscopy (FTIR), and field-emission secondary electron microscopy (FE-SEM). XRD pattern reveals of doped ZnO nanostructures reveal a peak related to Zn 2 Mn 3 O 8 phase along with peaks related to pure ZnO. Average particle size, estimated using Scherer formula, increases with Mn-doping. FE-SEM reveals morphological change from spherical particles (~15-20 nm) to nano-rods then nano-belt like 2 D super lattice structure after doping. Optical band gap obtain from Tauc's plot is 3.82, 2.05, 2.1 and 2.47 eV for pure-ZnO and Mn-doped samples with 13×10 17 , 20×10 17 and 32×10 17 Mn atoms/cm 3 , respectively. Presence of vibration band from 665 to 680 cm -1 in FTIR spectra endorses metal oxide formation. Nanomaterials were screen printed over working electrode of pre-fabricated three terminal electrode. This was used for electrochemical detection of myoglobin (Mb); a biomarker for acute myocardial infarction and were tested for Mb concentrations from 0-15 nM using cyclic voltammetry and electrochemical impedance spectroscopy. Redox current and charge transfer resistance varied linearly with Mb concentration. 7-fold increased sensitivity towards Mb in Mn-doped ZnO sensors is attributed to doping induced stress in nanostructures. Maximum sensitivity of 95μA-cm -2 nM -1 with LOD of 0.35 nM is observed for ZnO with 13 × 10 17 Mn atomic/cm 3 . Response time of ~10 ms is observed. Interference carried out with 7 nM Cytochrome c and 5 mM HSA reveal different oxidation potential and current value for Mb.

The role of cerium intercalation in the efficient dry exfoliation of graphene layers at a low temperature

Reduced graphene oxide (rGO) was efficiently exfoliated to a few-layer graphene by using Ce as an intercalant. Cerium was intercalated into graphene oxide by a co-reduction method to produce Ce-intercalated rGO. Fast exfoliation of the dried Ce-intercalated rGO was induced by heat treating it in an Ar atmosphere, at a specific temperature of 170 °C within 5 s. The exfoliation process was dependent on the drying method of the Ce-intercalated rGO. Morphological, crystallographic and surface chemical analyses of rGO, Ce-intercalated rGO and Ce-exfoliated graphene were analyzed by using field emission secondary electron microscopy (FE-SEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), Fourier-transformed infrared spectroscopy (FTIR), N2 adsorption-desorption isotherm and X-ray diffraction (XRD), in order to elucidate the reaction mechanism involved in the present fast dry exfoliation. Due to its process simplicity, the exfoliation is scalable to produce larger quantity of few-layer graphene.

Synthesis of NiMoO4/3D-rGO Nanocomposite in Alkaline Environments for Supercapacitor Electrodes

Although Graphene oxide (GO)-based materials is known as a favorable candidate for supercapacitors, its conductivity needs to be increased. Therefore, this study aimed to investigate the performance of GO-based supercapicitor with new methods. In this work, an ammonia solution has been used to remove the oxygen functional groups of GO. In addition, a facile precipitation method was performed to synthesis a NiMoO4/3D-rGO electrode with purpose of using synergistic effects of rGO conductivity properties as well as NiMoO4 pseudocapacitive behavior. The phase structure, chemical bands and morphology of the synthesized powders were investigated by X-ray diffraction (XRD), Raman spectroscopy, and field emission secondary electron microscopy (FE-SEM). The electrochemical results showed that the NiMoO4/3D-rGO(II) electrode, where ammonia has been used during the synthesis, has a capacitive performance of 932 Fg−1. This is higher capacitance than NiMoO4/3D-rGO(I) without using ammonia. Furthermore, the NiMoO4/3D-rGO(II) electrode exhibited a power density of up to 17.5 kW kg−1 and an energy density of 32.36 Wh kg−1. These results showed that ammonia addition has increased the conductivity of rGO sheets, and thus it can be suggested as a new technique to improve the capacitance.

Nano composite foam layer of CuO/graphene oxide (GO) for high performance supercapacitor

In this study, a facile and reproducible method has been developed to synthesize a nano composite foam layer of CuO/ graphene oxide (GO) intended for supercapacitor applications. GO particles were deposited on elecroplated CuO foam layers through electrophoretic deposition (EPD). The results showed that by varying EPD time (1, 3, 7 min), the degree of coverage of the foam layer with GO changes. This makes it feasible to manipulate the specific capacity of (Csp) CuO foam layers (238.3 F.g−1). It was shown that the specific capacity of the foam layer has been improved by amounts of 72%, 49% and 40% for EPD time deposition of 1, 3 and 7 min of GO, respectively.The results suggest a new versatile design to enhance super capacity and energy storage properties in conventional transition metal oxides. Morphology, phase structure, porosity and surface area of synthesized structures were investigated by field emission secondary electron microscopy (FE-SEM), X-ray diffraction (XRD) and BET (Brunauer– Emmett–Teller) approaches. Super capacity properties of the layers were from cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) tests.

Effect of diffusible hydrogen content on embrittlement of P92 steel

In the present investigation, varying electrode conditions (dried and contaminated) have been employed during welding of P92 steel to study the effect of diffusible hydrogen level on hydrogen-assisted cracking (HAC). Shielded metal arc welding process was employed to deposit the metal on a P92 steel plate. To evaluate HAC, the Granjon implant test with varying diffusible hydrogen content in the deposited metal was utilized. The diffusible hydrogen level was measured in the deposited metal by using the mercury method. Lower critical stress (LCS), embrittlement index (EI) and normalized critical stress ratio were evaluated from the Granjon implant test. The fracture surface morphology of fractured implant specimens has been studied by using a field emission secondary electron microscope. The P92 steel plate welded by the contaminated electrode with a high level of diffusible hydrogen was found to be more susceptible to HAC. As diffusible hydrogen content increased in the deposited metal, the LCS value and EI were observed to be decreased.

Structural and Optical Properties of Ultra-high Pure Hot Water Processed Ga2O3 Thin Film

Thin film based gas sensor is an advanced application of thin film especially Ga2O3 (GO) thin film gas sensor is useful for high temperature gas sensor. The effect of moisture or environment on thin film properties has more influence on gas sensing properties. Radio Frequency sputtered Ga2O3 thin film was synthesized and processed in ultra-high pure hot water at 95 °C for different time durations. The structural properties were verified by the Xray Diffraction technique and the observed spectra revealed the formation of hydroxyl compound of Gallium (Gallium Oxide Dueterate – GOD) on the surface of the thin film and evidenced for structural defects as an effect of moisture. Decreased crystallite size and increased dislocation density was showed the crystal defects of prepared film. From the Ultra Violet – Visible spectra, decreased optical transmittance was noticed for various processing time. The formation of needle like GOD was confirmed using Field Emission Secondary Electron Microscope (FESEM) images.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.7186

Ion beam mixed oxidation protective coating on Zry-4 cladding

In this study, SiC was coated on the surface of Zry-4 cladding to improve the oxidation protectiveness. In the coating of SiC onto Zry-4, the prime concern was adhesion at an elevated temperature. Here, a 70keVN ion beam was irradiated onto a SiC coating layer of ∼100nm in thickness; this was deposited via the e-beam evaporation method. Additional coating to a target thickness was then carried out. The films deposited without ion-beam mixing (IBM) often peeled-off at an elevated temperature, while the IBM SiC film always adhered to Zry-4, even after heating to ∼1000°C; at such a temperature, however, cracks formed in the film. X-ray photoelectron spectroscopy (XPS) analysis showed that the deposited SiC film contained about 20at.% of O, while after annealing in air, 76at.% of O was found on the surface layer. This implied that both the surface of SiC film and Zry-4 in the crack lines were oxidized. Comparing the Zr3d peak positions across the interface, a shift of binding energy by ∼1eV was detected, representing that, in view of favorable thermodynamics, SiC/Zry-4 seems to be an acceptable system to apply IBM. To heal the crack, the process of IBM for a 1μm thick coating and annealing was repeated. High-resolution field emission secondary electron microscopy (FE-SEM) showed that the crack lines, the main places at which oxidation occurred, were gradually covered as the process was repeated, ensuring enhanced oxidation protectiveness.

P70] Diffusion study on Mg-based alloys: an experimental and modeling approach

Magnesium alloys are receiving global attention in transportation sectors thanks to their superior light weight capacity which allows the design of fuel efficient vehicles with lower CO2 emissions. To develop commercial Mg alloys and optimize their manufacturing processes, fundamental knowledge in thermodynamics and diffusion kinetics is indispensable. In these thermally activated processes, diffusion can play a key role in the optimization of process parameters. A good knowledge of diffusion is thus imperative to understand the relationships between the microstructure and the high temperature process parameters. In the present study, diffusion kinetics of Mg alloys was investigated by both experiments and simulations.Pure magnesium has an hcp crystal structure (c/a ratio = 1.6236) and as a result, self-diffusion of Mg shows anisotropic behavior. Anisotropic diffusion is also observed for various alloying elements such as Ag, Cd, In, Sb, and Sn in hcp Mg. Apart from Ag, the diffusion of solute elements and Mg itself along the a-axis of Mg is faster than along the c-axis. However, the anisotropic behavior of the most common alloying elements like Al and Zn has not been investigated so far. Moreover, no data are available for rare earth elements (REE) despite the fact that their importance is increasing in Mg alloys.In the present study, the anisotropic impurity diffusion coefficients of Al, Zn, Gd, and Y were found to follow the same trend as Mg-self diffusion. The diffusion coefficients along the a-axis is maximum and is about 1.3 times faster than along the c-axis in the conventional material processing temperature. In addition, the effect of the basal plane orientation of Mg on Al and Zn diffusion was investigated and it was found that the diffusion coefficients of Al and Zn in hcp Mg decrease linearly with an increase of the tilting angle of the basal plane. Interdiffusion coefficients and growth constants of all binary intermetallics in Mg-Al, -Zn, -Gd, and –Y systems were also obtained from diffusion couple experiments.The grain boundary diffusion of Al at high angle grain boundaries in polycrystalline Mg was also investigated with diffusion couple experiments. To obtain Al concentration profiles at the grain boundary, high resolution cold field emission-secondary electron microscope (CFE-SEM) energy dispersive spectroscopy (EDS) was used. Al diffusion at grain boundaries close to 75° misorientation is about two orders of magnitude higher than the one through for the bulk.In the present study, a multiphase diffusion couple simulation model was developed which can successfully explain the experimental results. A homogenization and dissolution model was also developed to explain the solution treatment process of Mg-Al and Mg-Zn alloys. The model was validated with the help of annealing experiments for the binary Mg-Al (3, 6 and 9 wt. % Al) and Mg-Zn (1.5, 4.0 and 5.5 wt. % Zn) alloys. The model was then extended to the ternary Mg-Al-Zn system to predict the homogenization and dissolution phenomenon for the AZ…

Dielectric and magnetic properties of xCoFe2O4–(1 − x)[0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3] composites

xCoFe2O4–(1−x)(0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3) composites with x=0.1, 0.2, 0.3 and 0.4 have been synthesized by solid state reaction method. X-ray diffraction analysis and field emission secondary electron microscopy have been used for structural and morphological analysis, respectively. The spinel CoFe2O4 and perovskite 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 phase could be identified in the composites. Two anomalies in dielectric constant have been identified: first one is close to ferroelectric to paraelectric phase transition of 0.5Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 ceramic and the other lies near the magnetic transition temperature of CoFe2O4. There is an increase in magnetocapacitance and saturation magnetization of the composites at room temperature with increase in CoFe2O4 content. The magnetoelectric coupling coefficient (γ) was approximated by Δϵ∼γM2 relation. The optical band gap energy of the composites decreases with increase in CoFe2O4 content.

Fabrication of Ag:TiO2Nanocomposite Thin Films by Sol-Gel Followed by Electron Beam Physical Vapour Deposition Technique

Ag:TiO2nanocomposite films have been synthesized by sol-gel method followed by electron beam physical vapour deposition. Targets for this deposition were prepared by a hydraulic press using a powder containing Ag and TiO2prepared by sol-gel technique. Microstructure, surface, and plasmonic properties of nanocomposite films were studied using glancing angle X-ray diffractometer, atomic force microscopy, field emission secondary electron microscopy, and UV-Vis spectroscopy. Microstructural study reveals that Ag nanoparticles are embedded in TiO2matrix consisting of mixed phases of anatase and rutile. Size estimation using Scherrer formula reveals that average crystallite size of Ag nanoparticles is 23 nm. Surface morphological studies indicate that deposited films are uniform and intact to the substrate and have very low value of root mean square roughness. Optical studies exhibit a surface plasmon resonance induced absorption band in visible region, which is the characteristic feature of Ag nanoparticles. The intensity of this absorption band is found to increase with the increase in deposition time. Multiple peaks observed in absorption band were explained using the concepts of extended Mie scattering. Preliminary experiments also suggested that these nanocomposite films exhibit promising photocatalytic properties, which can be used for water treatment.

Dyes in Vertically Aligned Carbon Nanotube Arrays for Solar Cell Applications

ABSTRACTThe infiltration of dissolved dyes into vertically aligned carbon nanotube arrays (va-CNT) is reported. The ultra hydrophobic surface of the CNT forest can be wetted and hence infiltrated for an appropriate choice of solvent. The dye-infiltrated CNT array forms a well ordered bulk-heterojunction structure for organic solar cells in which the CNT can act as a large electrode or, for appropriate energy levels, as an acceptor material. Derivatives of the small molecule copper phthalocyanine or the polymer poly(3-hexylthiophene) were used as dyes. Drop coating was chosen as the infiltration technique resulting in a completely embedded CNT forest. Field emission secondary electron microscopy analysis illustrates the final layer quality. Common electrical characterization under AM1.5 illumination proves photosensitivity and implies photovoltaic behavior of the composite.

Implementation of High Carrier Mobility in Al-N Codoped p-Type ZnO Thin Films Fabricated by Direct Current Magnetron Sputtering with ZnO:Al2O3Ceramic Target

In this study, Al-N codoped p-type zinc oxide (ZnO) thin films were deposited on Si and homo-buffer layer templates in a mixture of and gas with ceramic ZnO:(2 wt% ) as a sputtering target using DC- magnetron sputtering. X-ray diffraction spectra of two-theta diffraction showed that all films have a predominant (002) peak of ZnO Wurtzite structure. As the fraction in the mixed and gases increased, field emission secondary electron microscopy revealed that the surface appearance of codoped films on Si varied from smooth to textured structure. The p-type ZnO thin films showed carrier concentration in the range of , resistivity in the range of 131.2-2.864 , and mobility in the range of respectively.