Scientific Program

Conference Series Ltd invites all the participants across the globe to attend 9th Nano Congress for Next Generation Manchester,United Kingdom.

Day 1 :

Keynote Forum

Gerd Kaupp

University of Oldenburg, Germany

Keynote: Dilemma between ISO and physics in (nano)inden

Time : 9:30 - 10:00

Conference Series Nano Congress 2016 International Conference Keynote Speaker Gerd Kaupp photo
Biography:

Gerd Kaupp has completed his PhD from Würzburg University and Post-doctoral studies from Iowa State, Lausanne, and Freiburg University. He has privately continued his research on “AFM on rough surfaces”. He has published more than 300 papers in renowned journals and has been serving as an Editorial Board Member of several scientific journals.

Abstract:

Since 2000, it is experimentally found and since 2015, physically deduced that pyramidal/conical nanoindentations follow the law of normal force FN = k∙h3/2 but not constant h2 (h=indentation depth). However, the unsupported exponent 2 is still used by the ISO-14577 standard, that industry and government must obey, while it does not concur with physics. Also NIST (2009) continued using h2 for defi ning erroneous mechanical parameters in a tutorial, despite their curves supporting h3/2. Only the precisely validated k and h3/2 allow for a wealth of otherwise unachievable characterizations, such as initial surface eff ects, gradients, phase transitions, transformation energy and activation energy. Arithmetically, h3/2 reveals the 80/20 ratio of indentation- and long-range works, independent of material or method. Unfortunately, also ISO hardness and elastic modulus depend on false h2, and the diff erences between h2 and h3/2 are very large. Th us, present mechanical data from indentations create dilemma between ISO standards and physics. It is however possible to obtain the "physical hardness" solely from the penetration resistance k of the loading curve. All deduced mechanical parameters from indentations are in error when depending on h2 instead of h3/2. Miscalculated materials and composites against physics might be the reason for medical or technical failures even growing to disasters. How shall liabilities in these cases be judged and compensated? 50 years published data require the original data or at least loading curves to be corrected for the sake of daily safety.

Conference Series Nano Congress 2016 International Conference Keynote Speaker Michael Hietschold photo
Biography:

Prof. Dr. Michael Hietschold studied physics and completed Ph.D. 1976 in theoretical solid state physics at Technical University Dresden, Germany. He was a postdoc at Quantum Theory Group of Moscow State Lomonosov University, Soviet Union. Since 1993, he is a professor for Solid Surfaces Analysis and head of the Electron Microscopy Laboratory at the Institute of Physics, Technische Universität Chemnitz, Germany. His research interests are surface physics, nanophysics and ultramicroscopy. He was a guest professor at the National University Ho Chi Minh City, Vietnam, and also lecturing at Portland State University, Oregon, USA. Since 2008 he is advisor for the National Metals and Materials Technology Center (MTEC), Pathumthani, Thailand. Michael Hietschold is a referee for many international scientifi c journals and research funding organizations and has published about 250 scientific papers. h-index: 27.

Abstract:

The investigation of self-assembled periodic adsorbate structures on crystalline substrate surfaces is a classical topic of surface physics which has been dominated for a long time by diff raction techniques. Th e appearance of scanning probe microscopies – especially scanning tunneling microscopy (STM) – has opened the fascinating opportunity of direct realspace imaging with atomic or submolecular resolution. At the interface between a solution and a crystalline solid, solute (and sometimes also solvent) molecules may deposit in an ordered manner at the solid substrate surface. In-situ studies of the adsorption pattern created this way are possible by ambient STM with the tip immersed in a deposited solution droplet. As an example, trimesic acid (TMA) molecules solved in alkanoic acids may arrange in open adsorption patterns (chicken wire and flower structures) due to H bonding via carboxylic functional groups. At the liquid-solid interface, such type of polymorphism may be controlled by the nature of the solvent (especially its polarity) as well as the concentration of the solutions which opens access to further novel structures. By a controlled increase of molecular packing density of solutions of TMA in alcohols, even a surface-reaction of TMA with coadsorbed solvent molecules (monoester formation with undecanol) has been observed. Recent investigations concerning substrate temperature during deposition and replacement of trimesic acid by the nonplanar benzene-triphosphonic acid will be discussed also. Another approach is based on the self-assembly of molecules at the crystalline surface in ultra-high vacuum (UHV). Under such “ideal conditions” the local electronic structure at the adsorbatesubstrate interface can be studied in detail by scanning tunneling spectroscopy (STS)offering insighte.g.into highly localized donation-backdonation charge transfer processes. We demonstrate some examples for the adsorption of phthalocyanines and porphyrines on metal surface. As an example, shows a temperature-induced polymerization in a monolayer of brominated Cu-Tetraphenylporphyrin on a Au(111) substrate. Such kind of investigations may open a way to better understanding the conditions of structure formation and control which is permanently encountered in the biotic world and which might become extremely fruitful for future engineering of molecular architectures and devices.

Conference Series Nano Congress 2016 International Conference Keynote Speaker Oliver G Schmidt photo
Biography:

Oliver G. Schmidt is a Director for the Institute for Integrative Nanosciences, IFW Dresden, Germany.

Abstract:

Nanomembranes are thin, flexible, transferable and can be shaped into 3D microtubular nanomembrane architectures. This makes them attractive for a broad range of applications and scientific research fields ranging from novel hybrid heterostructure devices to ultra-compact 3D systems both on and off the chip. If nanomembranes are diff erentially strained, they deform themselves and roll-up into microtubular structures upon release from their mother substrate. Rolled-up nanomembranes can be exploited to rigorously compact electronic circuitry and energy storage units. They can also serve as ideal platform to study novel photonic and plasmonic phenomena. As rolled-up microtubes can be easily tuned into the size range of single cells, they are perfectly suited to study single cell behavior in ultra-sensitive yet fully integrative lab-in-atube systems. As off-chip components they address exciting environmental and biomedical applications such as biomimetic regenerative cuff implants or powerful self-propelling microautonomous systems. If magnetic tubes or helices are combined with spermatozoa, such hybrid micro-biorobotic motors off er new perspectives towards paradigm shift ing reproduction technologies.

Keynote Forum

Xuewen Shu

Huazhong University of Science and Technology, China

Keynote: Huazhong University of Science and Technology, China

Time : 12:00 -12:30

Conference Series Nano Congress 2016 International Conference Keynote Speaker Xuewen Shu photo
Biography:

Xuewen Shu has completed his PhD from Huazhong University of Science and Technology (HUST), China. He worked as a Senior Scientist at Aston University & Indigo Photonics Ltd., UK during 2001-2013. He is currently a full Professor at HUST. He has published more than 150 papers in reputed journals and conferences and has been serving as an Editorial Board Member for two international journals.

Abstract:

Femtosecond-laser inscription/machining technology emerged in recent years as very powerful tool to fabricate microscale/nanoscale structures in transparent and nontransparent materials. Compared with conventional UV-laser inscription technology, fs-lasers can off er some unique advantages. First, the nonlinear nature of the absorption confi nes any induced changes to the focal volume. The spatial confi nement, combined with laser-beam scanning or sample translation, make it possible to micromachine geometrically complex structures in three dimensions. Second, the absorption process is independent of the material, enabling optical devices to be fabricated in compound substrates of diff erent materials. Third, the regions treated by fs-laser have a remarkably high etching rate compared with pristine material, which enable the flexible fabrication of holey structures such as microchannels. Since intense femtosecond laser pulses enable highly localized material modifi cation virtually in any material, it can thus be an excellent tool for the micro- and nano- fabrication of microstructures in a variety waveguides. In this paper, we will discuss some nano- and micro-structure made in diff erent waveguides and material using femtosecond laser. We will also discuss their functionality and potential applications.

  • Advanced Nanomaterials ; Nano Materials Synthesis and Characterisation ; Nano Medicine and Nano Biotechnology ; Nanotech for Energy and Environment ; Nano Science and Technology ; Nano Computational Modelling

Chair

Gerd Kaupp

University of Oldenburg, Germany

Co-Chair

Jorg Kroger

Technical University of Ilmenau, Germany

Session Introduction

Dongsheng Li

Pacifi c Northwest National Laboratory, USA

Title: In situ investigations of particle-mediated crystal growth
Biography:

Dongsheng Li completed her PhD in 2005 from Penn State University, majoring in Material Science and Engineering. Her PhD research focused on nanomaterials synthesis and characterization. She spent three years at Lawrence Berkeley National Laboratory as a Project Scientist, developing methods with in situ TEM and AFM to investigate particle nucleation and growth, and particle mediated crystal growth. She is currently a Staff Scientist at Pacifi c Northwest National Laboratory. She has published over 30 papers in respected journals and has been serving as a reviewer for journals such as Journal of Physics, Nanotechnology and the Journal of the American Ceramic Society, etc.

Abstract:

Assembly of molecular clusters and nanoparticles in solution is now recognized as an important mechanism of crystal growth in many materials, yet the assembly process and attachment mechanisms are poorly understood. To achieve this understanding, we are investigating nucleation and assembly of iron and titanium oxides using in situ and ex-situ TEM, and the forces that drive oriented attachment between nanocrystals and the factors that control them via AFM-based dynamic force spectroscopy (DFS). Our hypothesis is that attachment is due to reduction of surface energy and the driving forces that bring the particles together are a mix dipole-dipole interactions, van der Waals forces, and Coulombic interactions. Th erefore, they can be controlled via pH, ionic strength (IS), and ionic speciation. In-situ TEM shows that, in the iron oxide system, primary particles interact with one another through translational and rotational diff usion until a near-perfect lattice match is obtained either with true crystallographic alignment or across a twin plane.  Oriented attachment then occurs through a sudden jump-to-contact. Analysis of the acceleration during attachment indicates it is driven by electrostatic attraction. situ TEM analysis shows that the TiO2 nanowire branching occurs through attachment of anatase nanoparticles to rutile wires on a specific  crystallographic plane for which the anatase-to-rutile transformation leads to creation of a twin plane. Initial DFS measurements of the forces between (001) crystal basal planes of mica, and (001) planes of TiO2 show that the forces have strong relationship to pH, IS, and crystal orientation.

Biography:

Aladin Ullrich has completed his PhD from Augsburg University, Germany. He is the Co-ordinator of the Nano Research Group by Prof. Dr. S Horn, at the University of Augsburg, Germany.

Abstract:

We have investigated the influence of synthesis parameters on the properties of transition metal oxide nanoparticles prepared by thermal decomposition of metalorganic precursors in high-boiling solvents (Tboil>300°C). The focus of the work was on the production of monodispersed iron and manganese oxide particles. By varying synthesis parameters, ferrite as well as core/shell particles, in the size range from <10 up to 20 nm with different composition and different shapes were produced. Size, shape and composition were investigated using energy fi ltered Transmission Electron Microscopy (TEM). Electron diffraction as well as X- ray diff raction was used for crystal structure analysis. Magnetic properties of the particles were investigated by SQUID magnetometer. An exchange bias was found for particles with an antiferromagnetic/ferromagnetic interface, while ferrite (MnxFe2-x)FeO4 particles showed a tunable saturation magnetization depending on the Fe/Mn ratio. Various applications, like in the fi eld of polymer processing, will be discussed.

Biography:

Dominic Tessier is a renowned industry expert with extensive experience in the fi eld of surface treatments, coatings, polymers and fi bers. He is working as a Senior Scientist at CTT Group which involves problem-solving, mentoring, consultation, and the formulation and facilitation of projects. Currently, he is a Professional Chemist, Member of ASTM Technical Committee E35 on Pesticides, Antimicrobials, and Alternative Control Agents and F23 on Personal Protective Clothing and Equipment.

Abstract:

Coatings for self-cleaning fabrics and garments are becoming progressively important because they point toward the ideal situation where minimal washings, care and repairs are needed. The self-cleaning property will lead to the reduction soap, water and energy required for washings; this reduction is desirable to preserve the resources, the environment and extend the lifetime of fabrics and garments. The self cleaning property of textiles was for many years associated with superhydrophobic surfaces – a phenomenon first observed in the lotus leaf and so named the lotus effect. In this work, we present crystalline nano-structured ZnO clusters, synthetized from a microwave accelerated reaction (Zaman et al; 2013) that were used as a colloidal suspension for the preparation of self-cleaning formulations. The aqueous formulations were applied in a dip-coating process to different textile fabric blends. The intended benefit from such nano-structured ZnO clusters is to produce a micro-roughness and a nano-structure on the surface of the fibers. Wettability studies on the finished fabrics were  made by water contact angle measurements and standard test methods such as AATCC 22 (Water Repellency, Spray Test) and AATCC 118 (Oil repellency, Hydrocarbon Resistance Test). Surface morphology analysis was performed by SEM. The effect of repeated washings and resistance to abrasion will also be presented.

Biography:

Haider Butt is a Lecturer (Assistant Professor) at the University of Birmingham, UK. Previously, he was a Henslow Research Fellow at the University of Cambridge, from where he received his PhD degree in April 2012. He has published over 45 peer-reviewed journal papers and around 25 conference publications. His research work focuses on photonic devices based on nanostructures like carbon nanotubes, graphene and plasmonic nanostructures. His research work has received substantial recognition in the form of awards and media interviews. He has secured several prestigious research awards including Philip Leverhulme Prize.

Abstract:

Nanostructures due to their vast applications have been the focus of enormous research in the past decade. Th e key challenge for producing nanostructures based commercial applications is the scaling up of the fabrication process. We present the fabrication of ink based nanostructures by using the fast and commercially viable method of holographic laser ablation. A pulsed laser beam was irradiated onto a glass substrate coated with a thin semi-absorbing coating (ink or gold thin fi lms), which was to be nanopatterned. Th e beam is passed through the sample and is refl ected from the mirror below. Interference occurs between the two laser beams traveling in opposite directions, resulting in an interference pattern which ablates a well-ordered grating on to the surface. Th e period of the grating is determined by the incident wavelength (λ) and tilt angle (θ) of the sample with respect to normal incidence. In this manner, we recorded various holographic nanopatterns onto thin fi lms of ink/gold. Using this quick, scale and economical method, we produced several nanophotonic devices, such as optical gratings, lenses and holograms.

Jorg Kroger

Technical University of Ilmenau, Germany

Title: Manipulating and characterizing matter at the atomic scale
Biography:

Jörg Kröger has completed his PhD from Rheinisch-Westfälische Technische Hochschule Aachen (Germany). Since 2010, he has been holding a Chair in Experimental Physics at the Technical University of Ilmenau (Germany), where he is currently the Director of the Institute of Physics. He has published more than
100 papers in reputed journals and has been serving as an Editorial Board Member of Scanning and Journal of Nanoscience and Nanotechnolgy.

Abstract:

The scanning tunnelling microscope (STM) enables imaging of surfaces with atomic precision, the spectroscopy of electronic states and vibrational quanta with high energy resolution and the manipulation of matter at the single-atom and single-molecule level. Combining these opportunities in a single experiment is particularly appealing. Th is study will present two examples. The local injection of electrons into a single phthalocyanine molecule adsorbed on graphene-covered Ir(111) induces the abstraction of pyrrolic hydrogen. While the geometric confi guration of the molecule stays invariant, its electronic structure changes considerably. The combination of STM data and density functional calculations unravels the entire depopulation of the highest occupied molecular orbital upon the single-molecule reaction. A new view on electron confi nement at metal surfaces is provided by scanning tunnelling spectroscopy (STS) a top buried nano-cavities at Pb(111). Diff erential conductance data measured by STS show signatures of vertically confined quantum well states. Characteristic spectroscopic fi ne structure reveals additional quantization, which unexpectedly arises from quantum well refl ection at the open boundary where the thin Pb fi lm above the nano-cavity recovers its bulk thickness. Lateral confinement is thus achieved without confi ning potential.

Y Hancock

University of York, UK

Title: Nanographene device design
Biography:

Y Hancock obtained her PhD in 2003 at Monash University in Theoretical Quantum Physics and Engineering of Nanoscale Technologies. After completing a Postdoc at Monash, she moved to Aalto University (2006-2009) where she became Research Manager of a large-scale collaboration with Nokia supervising projects on next-generation mobile technologies. In 2009, she was appointed as Lecturer at the University of York where she works with her group on graphene studies and in the fi eld of biomedical research.

Abstract:

Advances in the production of nanographene using top-down fabrication, e.g., e-beam lithography, or by bottom-up, surfaceassisted chemical synthesis have provided much impetus to directly link theory and experiment. The benefits are two-fold. On the theoretical-side this allows the development of more accurate models by direct comparison of simulation with experimental measurement. Such comparisons are vital for understanding the ‘missing’ physics in the theoretical modelling of nanographene. On the experimental side, the creation of accurate, theoretical design tools can greatly reduce experimental trial and error, thus opening the potential for effi cient quantum engineering and device discovery. Th eoretically-informed experiments can also circumvent time consuming and often expensive procedures in determining specific features (size, functionalisation, patterning, etc.) for targeted applications and new intellectual property. To meet these aims, we have developed a computationally and physically transparent minimal model for nanographene coupled to a ‘graphene user interface’ or GRUI. Th e minimal model is computational efficient against density functional theory, and can reach large unit cell sizes for realistic modelling. Th e GRUI can also be directly interfaced with experiment and employed for rapid predictive simulation in nanographene device design. We will demonstrate the accuracy of the method and portray example results (e.g., spin transport) pertaining to our work on patterned and defected graphene nanoribbon devices (top-down), and for chemically-synthesised nanographene (bottom-up) determined via directed, kinetic self-assembly simulation.

Biography:

Uma Batra is Professor and Head of Department of Materials & Metallurgical Engineering and Dean of Faculty Affairs at PEC University of Technology, Chandigarh, India, a premier institute with a history of more than 100 years. Signifi cantly PEC is the alma mater of the late Indo-American astronaut and Aeronautical Engineering student Kalpana Chawla. Her research areas include nano hydroxyapatite for bioimplants, bioactive coatings on metallic implants. She has authored more than 100 research papers in national and international journals. She has delivered more than 50 invited talks in the area of Metallurgy and Materials. She was nominated offi cially in 2007 as the first Indian Woman Engineer representative to the U.S Society of Women Engineers (SWE) US by a delegation from the American Society of Engineering Education.

Abstract:

The present work deals with the development of hydroxyapatite (n-HA) and hydroxyapatite-chitosan composite (n-HACs) nanostructres for removal of lead ions from aqueous lead containing solutions. The synthesis of n-HA was carried out using solgel route while the n-HACs was prepared by a co-precipitation method. Th e nanostructures were characterised using transmission electron microscopy, X-ray diff raction, fourier transform infrared spectrophotometry and thermogravimetric analysis to reveal the morphology, crystal structure, functionality and stability respectively. In order to evaluate the lead removal characteristics of n-HA and n-HACs, adsorption tests were conducted and the results showed better performance of n-HACs than n-HA. The equilibrium Pb+2 ions concentration was identifi ed by atomic absorption spectroscopy. Th e infl uence of initial Pb+2 ion concetration, and sorbent dosage on sorption capacity was studied. The kinetics of the sorption process was also investigated. Two models of adsorption isotherms (Freundlich and langmuir) were employed to corelate the results and to understand the  adsorption mechanism. Adsorption kinetics and isotherm tests revealed that Pb+2 adsorption to the n-HACs follows pseudo-seond order kinetic and Langmuir-type adsorption respectively.

B Huber

Munich University of Applied Sciences, Germany

Title: Inkjet printing of redox-based resistive switching memory
Biography:

B Huber holds BSc and MSc degrees in Physics from the Technical University of Munich. Since fall 2015, he has been working toward the PhD degree at the Munich University of Applied Sciences in collaboration with the Institut National de la Recherche Scientifi que (INRS) in Montréal. His research interests are in fabrication and characterization of inkjet printed electrochemical memory using various materials

Abstract:

Until now, any computer calculation is hampered by the basic computer architecture: All data has to be shift ed back and forth between fast but volatile random access memory (RAM) and the non-volatile but slow hard drive. Th e ultimate data memory combines non-volatile behaviour together with fast read and write access and a high integration density. Great potential lies in resistively switching memory cells, which consist of a conductor-insulator-conductor structure. By applying appropriate voltages, the cell resistance can be switched between at least two resistance states, corresponding to “0” and “1”. Th e non-volatile resistive memory off ers fast operation speed and low power consumption. We report inkjet printing of resistive memory cells, which provides two additional advantages: Firstly, the printing at ambient conditions makes cleanroom environment obsolete and considerably lowers the production costs. Secondly, printing on fl exible films opens the door to the up-and-coming fi eld of printed electronics, where resistive memory could be integrated in fl exible printed circuits. We use a standard FujiDimatix® 2831 inkjet printer for the printing of all 3 layers of our memory cells. For the conducting electrodes we use organic polymers and various commercial as well as in-house synthesized metal nanoparticle inks. The insulator layer consists of a printed methylsiloxane polymer. As a substrate we use rigid silicon wafers and fl exible polyimide fi lms. Th e cells show the potential for multi-bit data storage. With switching voltages below 3V and switching currents in the nanoampere regime, we already see a substantially lower power consumption compared to flash technology.

Biography:

Mikheil Mebonia has completed his Master’s from Ilia State University and started his PhD at the same university collaborating with RWTH Aachen University. Since 2014, he has been working in Juelich and Fraunhofer Institute of Laser Technology as a PhD Researcher. He is working in Scientifi c and Technological Centre "Nano Structured Materials for Renewable Energy" the School of Engineering in Ilia State University. He has published some papers in reputed journals.

Abstract:

Recently, new quantum features have been studied in the area of nanostructured layers. Nano-grating on the surface of the thin layer imposes additional boundary conditions on the electron wave function and induces G-doping or geometry doping. G-doping is equivalent to donor doping from the point of view of the increase in electron concentration ‘n’. However, there are no ionized impurities. Th is preserves charge carrier scattering to the intrinsic semiconductor level and increases carrier mobility with respect to the conventionally doped layer. We fabricated Si nano-grating layers and measured their electrical characteristics to monitor geometry induced doping (G-doping). Grating was fabricated using laser interference lithography (375 nm laser) followed by reactive ion etching of Si. Next, large square island (0.3 x 0.3 mm) was shaped in the device layer and four SiTiAg ohmic contacts were formed to measure electrical characteristics. Th e I-V characteristics were recorded using both 4 wire and 2 wire methods. Resistancetemperatureure Þ(T)  dependences (T = 300 K) were recorded as well. For all 12 samples, nano-grating layers showed 2-3 order of magnitude reduction in resistivity. Resistivity anisotropy was in the range 0.2-1 at 300 K. Obtained geometry induced doping level corresponds to “eff ective impurity” concentration of 3x1018 cm-3. Th e agreement with G-doping theory, Þ(T) dependence, is that it was observed (data from 12 samples) that nano-grating reduces resistivity of Si layer from  10 Ohm cm (plain layer) to 5x10-2- 8x10-3 Ohm cm. Th is reduction is in agreement with theoretical prediction of G-doping. Value 10-2 Ohm cm corresponds to “impurity” concentration of 3x1018 cm-3 (Phosphorous in Si). G-doping does not requires ionized impurities. Th is allows high carrier mobility and temperature independent carrier concentration. Nano-grating fabrication does not require sophisticated technology and can be used for solar cells and other photovoltaic devices, ultra high frequency electronics and power electronics.

Biography:

Nabeel Almuramady is a PhD student at Cardiff University, and has completed his MSc from Al-Nahrain University in 2007.

Abstract:

Tooth surface of a silicon microgear MEMS (Micro Electro Mechanical Systems) working in the vacuum is modelled by a hierarchical structure of multiple blocks located at different levels. The level of each block is defi ned by the gap between tooth surfaces at each particular instance. The tooth block roughness is modelled at two scales specifi ed by character of interactions: Atomic scale; where chemical interactions occur at nanoscale; where vander Waals interactions are signifi cant. There was no plastic deformation of the tooth surface asperities due to their size and the Polonsky-Keer effect. Friction force and the coeffi cient of friction were calculated using the total energy dissipated during contact between tooth surfaces. Th e adhesion forces act within the so-called “Maugis adhesive layer”, and the force of adhesion is assumed to be equal to the pull-off force for a fl at asperity. Th e numerical simulations show that a high probability contact between clean surfaces in a vacuum environment leads to stiction because the maximum force produced by the MEMS is less than the force of surface’s tangential interactions. To avoid failure of the device of the tooth surfaces, it is suggested to functionalize the tooth surfaces by non-sticking monolayers because the stiction is mainly due to the so-called “cold welding” of clean crystalline materials. The numerical simulations showed that until the functionalizing monolayer is not worn away, the probability of stiction between the functionalized MEMS microgear teeth was greatly reduced.

Biography:

Zaynab N Alraziqi has completed her MSc degree in 2004 in Material Science from University of Technology-Baghdad. She worked as Assistant Lecturer at Applied Science Department-Universty of Technology since 2006. In 2013, she was awarded with a PhD scholarship from the Higher Committee for Education Development in Iraq (HCED). She has published 2 papers in national journals in Iraq. She gained a good experince in using Atomic Force Microscopy (AFM) through her PhD study.

Abstract:

Abilities of Atomic Force Microscope (AFM) tips to remove materials during nanomachining depends critically on the tip bluntness. To describe the actual shapes of AFM tips, four diff erent non-axisymmetric tips as received from the manufacturer were studied. Each tip was scanned first along a tip characterizer; and then it was used for depth-sensing nanoindentation of soft elastic polycarbonate (PC) samples. Th e tip characterizer is a special test structure consisting of an array of silicon sharp pin-like tips. The devices employed allowed us to extract very accurate data on the real shapes of the tips. Before the use of the tip characterizer, after its use, and aft er nanoindentation, two-dimensional Scanning Electron Microscope images of the tip profi les were obtained. The images showed that AFM tips were undamaged. The actual tip bluntness was characterized by approximation of the shape as powerlaw functions of degreed. Th e values of d extracted by the power-law fitting of the tips gave d ≈ 2. However, AFM tips are not fixed vertically but they are actually inclined by 12o to the cantilever beam. Applying the Borodich contact problem rescaling formulae to the load-displacement curves, one can also extract the degree d of the shape bluntness; the d values were in the range 3.4-4.5. These values were in agreement with the power-law fitting of the inclined tips. Th e inclination of the tip can aff ect suffi ciently the effectiveness of nanomachining. Bluntness of the AFM tips used for studying the surface topography can be also characterized by the above procedure.