Journal of Nano Research Vol. 17

Abstract: In the Current Study, the Structural Characteristics of Siox Thin Films Grown by Magnetron Sputtering on Si Substrates Are Reported. High Resolution Transmission Electron Microscopy Revealed the Formation of Amorphous Siox Films for the as-Deposited Samples, as Well as the Ones Annealed in Ambient Air for 30 Min at 950oC and of Si Nanocrystals, Embedded in Amorphous Siox, after Ar Annealing for 1-4 Hours at 1000oC. the Nanocrystals, with Sizes up to 6 Nm, Predominately Exhibit {111} Lattice Planes. Energy-Dispersive X-Ray Analysis Showed that the Si/O Ratio Is between 0.5-1, I.e. the Amorphous Films Comprise of a Mixture of Sio2 and Sio. Phase Images and Corresponding Strain Maps Created Using Fourier Filtering Revealed a Uniform Contrast in the Nanocrystals, which Shows that the Si Lattice Constant Does Not Vary Significantly. the Residual Strain Variations, around 4%, May Account for the Possible Existence of a Small Percentage of Highly Disordered Si or Siox Residual Clusters inside the Regular Si Matrix, in Full Agreement with Photoluminescence Measurements Performed on the same Materials.

Abstract: Multiple Patterning Seems to Be One of the Most Promising Solutions for the Gap between the 193 Nm Immersion Lithography and the 13.5 Nm EUV Lithography for Industrial Manufacturing of Ultra Large Scaled Integrated CMOS Circuits [1]. the Used Techniques in this Paper Lead to an Excellent Homogeneity and Uniformity of the Channel Length and Width which Enables a Fundamental Statistical Analysis of the Electrical Transistor Parameters. the Process Flow Has Been Optimized to Minimize the Active Channel Area and to Achieve a Sufficient Yield for a Trustworthy Statistical Analysis. while the Channel Length Is Defined by a Single Deposition- and Etchback Technique the Active Area Is Defined by a Composition of Multiple Spacers that Lead to a Diffusion Stop Barrier. the Statistical Analysis of these Devices Shows Dramatically Increasing Fluctuations of the Threshold Voltage if the Device Dimensions Are Decreased.

Abstract: We Report on the Structural and Vibrational Properties of the X = 0.11 and X = 0.33 Compositions of a New Class of Nanostructured Thermoelectric System (PbTe)1-X(PbSnS2)x by Means of X-Ray Diffraction, Scanning and Transmission Electron Microscopy and Infrared Reflectivity. both Compositions Are Phase Separated, where Pbsns2 Self-Segregates from Pbte to Form Features with Dimensions Ranging from Tens of Micrometers to Tens of Nanometers. Effective Medium Approximation Was Used in Order to Determine the Volume Fraction and the Dielectric Function of the Nanoscale Pbsns2 Embedded in Pbte. by Comparing the Phonon Parameters of the Nanoscale Pbsns2 and Bulk Pbsns2 Single Crystals, we Concluded that Phonon Confinement Effects and Bilayer Thickness Anisotropy within the Pbsns2 Nanostructures Embedded within Pbte Are Responsible for the Observed Variations in the Frequencies of the Shear and the Compression Modes Not Observed in Pure Crystals of Pbsns2.

Abstract: In this Work, Mg2si/MgO Nano-Composites Were Prepared by Co-Sputtering of Mg and Si Targets on Si {100} Substrates Using Dual Cathode Magnetron Sputtering. Films Were, Subsequently, Annealed at 380°C and 500°C for 4 Hours in Ar Gas Atmosphere. Various Mg/Si Sputtering Power Ratios Have Been Examined. Grown Films Were Characterized by XRD, SEM/EDS, and IR Reflectivity Measurements.

Abstract: Two Oxide Semiconductors, Namely, Bismuth Vanadate (BiVO4) and Silver Bismuth Tungstate (AgBiW2O8) Were Prepared by Solution Combustion Synthesis and their Attributes as Photocatalysts Were Comparatively Evaluated. A Key Conclusion of this Study Is that the Optical Characteristics Alone Provide only a Partial Glimpse into the Applicability of a Given Semiconductor for Solar Energy Conversion and Environmental Remediation. Thus while the Optical Bandgap of Bivo4 Is Lower than Agbiw2o8 (and Thus Is Able to Harness a Greater Portion of the Solar Spectrum), its Photocatalytic Activity for the Degradation of a Dye Is Inferior. this Finding Underlines the Fact that other Characteristics of the Semiconductor (band-Edge Alignment, Surface Quality Etc) Also Play as Critical a Role as the Optical Properties.

Abstract: Multilayered, Gradient Tialsin-Based Nanocomposite Coatings Have Been Developed and Investigated with Respect to their Applicability in the Machining Industry. the Main Coating Layer Was Composed of 5-8 Nm Tin and Aln Nanograins. the Coating Possessed Hardness as High as 40 GPA, which Allows it to Be Classified as Superhard. during Heating up to 900oC in Air in Steps of 100oC for 6 H at each Temperature, the Coating Showed Good Stability up to 700oC. Thermal Treatment over this Temperature Caused a Decrease in the Hardness to Values Characteristic for Tialn Multilayered Coatings, while the Adhesion to the Substrate Remained Steady.

Abstract: Al-Free Nanolayered Metallizations Based on the Transition Metals Ti, Mo, Ni and Pd, with Varied Ti Content, Have Been Developed as an Alternative of the Al-Based Contacts for Sub-Micron Hemts. the Electrical, Morphological and Thermal Properties of the Metallization Schemes Have Been Studied with the Aim of Obtaining the Most Suitable Combination of Low Resistivity, a Smooth Surface and an Acute Edge. the Lowest Resistivity of 8.8x 10-6 Ω.cm2 Has Been Determined with the Ti/Mo/Ti/Au Contact, while the Lowest Surface Roughness of 6 Nm Has Been Measured for the Ti/Ni/Ti/Au Metallization. these Contact Schemes Have Shown much Better Edge Acuity in Comparison to the Al-Based Metallizations.

Abstract: In this Work we Have Compared the Effects of Physical Activation with CO₂ and Chemical Activation with KOH on Porosity Development in Vapor Grown Carbon Nanofibers (CNFs). both Physical and Chemical Activations Result in Micro- and Mesoporosity Development in the Studied Cnfs. under this Work’s Conditions, Chemical Activation with KOH Was More Efficient than Physical Activation with CO₂ in Terms of Surface Area Increase Regarding the Fresh Material (7.5-Fold versus 4-Fold, Respectively, under the Optimal Conditions Found for each Type of Activation). Atomic Force Microscopy Indicated that, although the CNF Samples Retained their Fibrous Morphology upon both Physical and Chemical Activation, the Latter Treatment Brought about Noticeable Changes in their Nanometer-Scale Structure. Likewise, an Appreciable Decrease in Nanofiber Diameter Following both Types of Activation Was Noticed. However, such Diameter Reduction Could Not Account for the Increase in Specific Surface Area of the Activated Materials, which Has to Be Attributed to Porosity Development. X-Ray Diffraction Studies Showed that both Physical as Chemical Activation Take Place Mainly on the Disordered Skin of the Cnfs but in a Different Way. Thus, Physical Activation Removes the More Amorphous Areas from the CNF Skin by Gasification (which Increases their Structural Order), while upon Chemical Activation with KOH, the Carbon Material Is Oxidized to a Carbonate, and the Alkali Hydroxide Is Reduced to Metallic Potassium, which Becomes Intercalated between the Graphene Layers of the Carbon Material, Leading to a Certain Expansion of the Structure.

Abstract: The widespread use of nanoparticles (NPs) in consumer goods could put these materials in the waste stream, potentially to soil and sediments. However, little is known about their transport in water and soils. In this study, transport behavior and attachment of ZnO NPs in soil components were studied through column experiments and sequential extraction, respectively. Bare and sodium citrate coated ZnO NP suspended in CaCl2 solutions at different ionic strengths, were passed through glass columns packed with sandy soils (SS) and sandy loam soils (SLS) and the effluents were analyzed by ICP-OES. The distribution of Zn in soil particles was studied by electron microprobe (EMP). Results showed that 99% of Zn/ZnO NPs was retained in SLS and 68% ~ 99% was retained in SS, for ionic strengths varying from 0 to 1 mM. Travel distances (cm) for bare ZnO NPs in SS and SLS were 19.2 and 5.3, respectively, while for coated NPs the distances were 21.4 and 6.9 cm, respectively. The surface coating reduced deposition rates from 0.73 to 0.65 and from 2.28 to 1.74 for SS and SLS, respectively. In both soils the amounts of uncoated NPs in the exchangeable fraction were less than 1%; however, 30% of coated NPs remained in the exchangeable fraction. EMP mapping showed that Zn/ZnO NPs associated with silica and aluminum, which are indicators of soil clay minerals. Long term observations are still needed to evaluate the bioavailability to plants of Zn released from coated and uncoated ZnO NPs.