NanoScience Session

1. Communication Technical College “Augustin Maior” Cluj-Napoca, Romania NanoScience Session

2. Nanotehnology And in this picture we can se a classically circuit board, bigger than the first picture we reprezented! In the picture below the imprimatet circuit it reprezent the nano variant of the big circuits.

3. Definition • Nanotechnology is the study of manipulating matter on an atomic and molecular scale. Generally nanotechnology deals with structures sized between 1 to 100 nanometer in at least one dimension, and involves developing materials or devices within that size. Quantum mechanical effects are very important at this scale.

4. Materials Perspective A number of physical phenomena become pronounced as the size of the system decreases. These include statistical mechanical effects, as well as quantum mechanical effects, for example the “quantum size effect” where the electronic properties of solids are altered with great reductions in particle size. This effect does not come into play by going from macro to micro dimensions.

5. NanoMaterials • Graphical representation of a rotaxane, useful as a molecular switch. • The nanomaterials field includes subfields which develop or study materials having unique properties arising from their nanoscale dimensions.

6. Researchers are looking into the following nanoelectronics projects: • Transistors built insingle atom thick graphene filmto enable very high speed transistors. • Combining gold nanoparticles with organic molecules to create a transistor known as a NOMFET (Nanoparticle Organic Memory Field-Effect Transistor). • Using carbon nanotubes to direct electrons to illuminate pixels, resulting in a lightweight, millimeter thick"nanoemmissive" display panel. • Making integrated circuits with features that can be measured in nanometers (nm), such as the process that allows the production of integrated circuits with 45 nm wide transistor gates.

7. Carbon NANO-TUBES • Using nanosized magnetic rings to makeMagnetoresistive Random Access Memory (MRAM)which research has indicated may allowmemory density of 400 GB per square inch. • Developingmolecular-sized transistorswhich may allow us to shrink the width of transistor gates to approximately one nm which will significantly increase transistor density in integrated circuits. • Usingself-aligning nanostructures to manufacture nanoscale integrated circuits. • Using nanowires to buildtransistors without p-n junctions.

8. IBM Scientists Demonstrate World's Fastest Graphene Transistor • This accomplishment is a key milestone for the Carbon Electronics for RF Applications (CERA) program funded by DARPA, in an effort to develop next-generation communication devices. • The high frequency record was achieved using wafer-scale, epitaxially grown graphene using processing technology compatible to that used in advanced silicon device fabrication. • Graphene is a single atom-thick layer of carbon atoms bonded in a hexagonal honeycomb-like arrangement. This two-dimensional form of carbon has unique electrical, optical, mechanical and thermal properties and its technological applications are being explored intensely. NANO-TRANSISTORS

9. An organic transistor paves the way for new generations of neuro-inspired computers • For the first time, CNRS and CEA researchers have developed a transistor that can mimic the main functionalities of a synapse. This organic transistor, based on pentacene and gold nanoparticles and known as a NOMFET (Nanoparticle Organic Memory Field-Effect Transistor), has opened the way to new generations of neuro-inspired computers, capable of responding in a manner similar to the nervous system. • In the development of new information processing strategies, one approach consists in mimicking the way biological systems such as neuron networks operate to produce electronic circuits with new features. In the nervous system, a synapse is the junction between two neurons, enabling the transmission of electric messages from one neuron to another and the adaptation of the message as a function of the nature of the incoming signal (plasticity). For example, if the synapse receives very closely packed pulses of incoming signals, it will transmit a more intense action potential. Conversely, if the pulses are spaced farther apart, the action potential will be weaker.

10. Motorola Labs Debuts First Ever Nano Emissive Flat Screen Display Prototype • The development of such a flat panel display is possible due to Motorola Labs Nano Emissive Display (NED) technology, a scalable method of growing CNTs directly on glass to enable an energy efficient design that excels at emitting electrons. Through this cost-effective process and design, Motorola showcases the potential to create longer-lasting NED flat panel displays with high brightness, excellent uniformity and color purity. • Motorola’s proprietary CNT growth process provides excellent precision in designing and manipulating a material at its molecular level – enhancing specific characteristics – and, in the case of flat panel displays, producing high-definition images. The electron emission performance demonstrated by the Motorola technology exceeds that achieved to date with the application of the CNT to the cathode via an organic paste, the process used by other companies.

11. Magnetoresistive random access memory • Unlike conventionalRAMchip technologies, in MRAM data isnot stored aselectric chargeor current flows, but bymagneticstorage elements. The elements are formed from twoferromagneticplates, each of which can hold a magnetic field, separated by a thin insulating layer. One of the two plates is a permanent magnet set to a particular polarity, the other's field can be changed to match that of an external field to store memory. This configuration is known as aspin valveand is the simplest structure for a MRAMbit. A memory device is built from a grid of such "cells". • It is also worth comparing MRAM with another common memory system,flash RAM. Like MRAM, flash does not lose its memory when power is removed, which makes it very common as a "hard disk replacement" in small devices such asdigital audio playersordigital cameras. When used for reading, flash and MRAM are very similar in power requirements. However, flash is re-written using a large pulse of voltage (about 10 V) that is stored up over time in acharge pump, which is both power-hungry and time consuming. Additionally the current pulse physically degrades the flash cells, which means flash can only be written to some finite number of times before it must be replaced.

12. Single molecule transistor could revolutionize electronic miniaturization • Researchers at the University of Alberta have proven the potential for constructing electronic circuitry on a molecular scale, a breakthrough that could shatter the limitations of conventional transistor technology and pave the way for smaller, faster, cheaper microelectronic devices. • The report by National Research Council National Institute of Nanotechnology's Molecular Scale Development Group, led by U of A physics professor and iCORE Chair in Nanoscale Information and Communication Technologies Dr. Robert Wolkow, has been published in the June 2005 issue of the scientific journal Nature. • Wolkow said his team has proven that a single molecule can be controllably charged while all the surrounding molecules remain neutral, causing it to act as a basic transistor. Transistors control the flow of current in most electronic devices and are combined to form integrated circuits used to make the microprocessors and memory chips that drive everything from computers and cell phones to household appliances.

13. Applications • One of the major applications of nanotechnology is in the area of nanoelectronics with MOSFET's being made of small nanowires ~10 nm in length. Here is a simulation of such a nanowire.

14. Nano Wires • A nanowire is a nanostructure, with the diameter of the order of a nanometer (10⁻⁹ meters). Alternatively, nanowires can be defined as structures that have a thickness or diameter constrained to tens of nanometers or less and an unconstrained length. At these scales, quantum mechanical effects are important — which coined the term "quantum wires". Many different types of nanowires exist, including metallic (e.g., Ni, Pt, Au), semiconducting (e.g., Sip, InP, GaN, etc.), and insulating (e.g., SiO2, TiO2). Molecular nanowires are composed of repeating molecular units either organic (e.g. DNA) • The nanowires could be used, in the near future, to link tiny components into extremely small circuits. Using nanotechnology, such components could be created out of chemical compounds.

15. Synthesis of nanowires • There are two basic approaches of synthesizing nanowires: top-down and bottom-up approach. In a top-down approach a large piece of material is cut down to small pieces through different means such as lithography and electrophoresis. Whereas in a bottom-up approach the nanowire is synthesized by the combination of constituent ad-atoms. Most of the synthesis techniques are based on bottom-up approach.

16. Conductivity of nanowires • The conductivity of a nanowire is expected to be much less than that of the corresponding bulk material. This is due to a variety of reasons. First, there is scattering from the wire boundaries, when the wire width is below the free electron mean free path of the bulk material. In copper, for example, the mean free path is 40 nm. Nanowires less than 40 nm wide will shorten the mean free path to the wire width.

17. Nanowires also show other peculiar electrical properties due to their size. Unlike carbon nanotubes, whose motion of electrons can fall under the regime of ballistic transport (meaning the electrons can travel freely from one electrode to the other), nanowire conductivity is strongly influenced by edge effects. The edge effects come from atoms that lay at the nanowire surface and are not fully bonded to neighboring atoms like the atoms within the bulk of the nanowire. The unbonded atoms are often a source of defects within the nanowire, and may cause the nanowire to conduct electricity more poorly than the bulk material.

18. Welding nanowires • To incorporate nanowire technology into industrial applications, researchers in 2008 developed a method of welding nanowires together: a sacrificial metal nanowire is placed adjacent to the ends of the pieces to be joined (using the manipulators of a scanning electron microscope); then an electric current is applied, which fuses the wire ends. The technique fuses wires as small as 10 nm.

19. Uses of nanowires • Nanowires still belong to the experimental world of laboratories. However, they may complement or replace carbon nanotubes in some applications. Some early experiments have shown how they can be used to build the next generation of computing devices. • To create active electronic elements, the first key step was to chemically dope a semiconductor nanowire. This has already been done to individual nanowires to create p-type and n-type semiconductors. • The next step was to find a way to create a p-n junction, one of the simplest electronic devices. This was achieved in two ways. The first way was to physically cross a p-type wire over an n-type wire. The second method involved chemically doping a single wire with different dopants along the length. This method created a p-n junction with only one wire.

20. Bottom-up approaches • Sarfus image of a ADN biochip elaborated by bottom-up approach. • These seek to arrange smaller components into more complex assemblies.

21. Top-down approaches • This device transfers energy from nano-thin layers of quantum wells to nanocrystals above them, causing the nanocrystals to emit visible light. • These seek to create smaller devices by using larger ones to direct their assembly.

22. Tools and Techniques • Typical AFM setup. A microfabricated cantilever with a sharp tip is deflected by features on a sample surface, much like in a phonograph but on a much smaller scale. A laser beam reflects off the backside of the cantilever into a set of photodetectors, allowing the deflection to be measured and assembled into an image of the surface.

23. Communication Technical College “Augustin Maior” Cluj-Napoca, Romania Nanoyou School 2010 - 2011 Project Nano Our School Team: Coordinator: prof. Lucia Gutu Students: Filip Bolba Sandor Francisc Alexandru Farcas Cornel Danci