An Investigation of Chemical Vapour Deposition of Graphene on a Copper Substrate

First a few general informations: Copper has the chemical symbol Cu,an atomic mass of 63.546 and 29 protons. This means that it has also 29 electrons. If 63.546 is rounded to 64 and 29 is subtracted from this, Copper has 35 neutrons. The melting point of copper is 1085 C°.

The name copper and the symbol Cu derive from the Latin word “Cuprum”, which by definition means the island of Cyprus. Copper is the 29th element and is located amongst the transition metals in the periodic table. Copper is one of the first elements both known and to be utilized by humans. It is believed that the reason for its early discovery was due to the element being able to naturally occur in its relatively pure form. Archaeological evidence has suggested that it was in fact the Mesopotamians somewhere between 5000 and 6000 years ago, which were able to fully utilize both extracting and making use of the element itself. A copper pendant was found in the Middle East and is dated 8700BC. There are many ways that copper can be used, as

During lab, we put the metal copper under different circumstances so that we could gain a better understanding as to what goes on in the copper cycle. Throughout each stage of the copper cycle, we deduced what type of chemical reaction took place based on observation, made observations about the state of the metal and what type of environment it was subjected to, and determined what the net ionic equation was for each stage. Following the experiment, we calculated what the percent yield was and compared the changes in mass from the initial stage to the final stage.

Copper, Cu, is the 29th element in the periodic table and has 29 protons. Its mass number is 63.55. It is a transition metal in the middle of the periodic table. The symbol for copper is "Cu", which comes from the Latin word cuprum, which came from the Latin word for the island of Cyprus, where copper was found. Copper can be found as a metal in the ground. It is found in small amounts in living things. Some mollusks and arthropods have blue blood because they have copper in their blood. Copper may be the oldest metal in use, as ancient copper tools have been found. Copper is used in electrical wiring, it’s also what the Statue of Liberty is made of. Copper does not corrode and is not as toxic as a metal. Copper compounds are toxic though,

From all of these uses, graphite also has the ability to conduct electricity, and we can the reason as to why when looking at the electron arrangement in graphite. As each Carbon atom bonds to three other Carbon atoms, there is a fourth electron remaining in the bonding level. These remaining electrons in each Carbon atom form into a “sea” of delocalised electrons, moving around the whole sheet of atoms in the one layer. It is the ability of these delocalised electrons to move freely through their own Carbon layer, hence, making graphite a good conductor of electricity. Being a good conductor of electricity graphite, can be used as electrodes to an arc lamp and to carry the electricity that heats electric arc furnaces.

Graphene is a form of carbon which has recently been receiving a great deal of attention. Some have come to call it “the wonder material” due to its many extraordinary properties. Although isolated in 2004, graphene's properties had been calculated decades earlier. It consists of a single layer of carbon atoms arranged in a hexagonal lattice. A single sheet of graphene is stronger than steel and yet remains very flexible, retaining all of its properties despite being bent and unbent multiple times. It is able to sustain extremely high electric current densities, is impermeable to all gasses, has a thermal conductivity double that of diamond and a very high electron mobility at room temperature. It is also easily chemically functionalized,

In 2004, two scientists prepared the graphene, a single planar layer of graphite, which has a double carbon atoms bonds. Each carbon atom joins itself with three atoms by strong σ covalent bonds, the strong carbon-carbon bonding granted graphene a rigid structure. With four valence electrons, each carbon atom can contribute one unbounded electron to form π bonds above the plane of the carbon sheet. Graphene layers arrange as hexagons and every hexagon is completely surrounded by other hexagons that are packed in a honeycomb crystal lattice as shown in Figure ‎1 3. Their thickness is about one atom thick [6] and their bond-length in the range of 0.142nm[7][8]. Thus, in 1 mm thick graphite, there are about 3 million graphene sheets[9]. The 2010 Nobel Prize in physics has been awarded to the two scientists: Andre Geim and Konstantin Novoselov from University of Manchester (UK) for their research in graphene - discovery. Also, the surface area of the single sheet is 2630 m2/g [10].

We demonstrate large monolayer tungsten disulfide (WS2) (> 200µm) by chemical vapor deposition. Photoluminescence (PL) and Raman spectroscopy provide insight into the structural and strain heterogeneity of the flakes. We observe exciton quenching at grain boundaries (GBs) that originate from the nucleation site at the center of WS2 flakes. Temperature variable transport measurements of top-gated WS2 transistors show an apparent metal-to-insulator transition. Variable range and thermally activated hopping mechanisms can explain the carrier transport in the insulating phase at low and intermediate temperatures. Devices exhibit room-temperature field-effect electron mobility as high as 48cm2/V.s. The mobility increases with decreasing temperature and begins to saturate at below 100°K, possibly due to Coulomb scattering or defects.

In this study, we use an effective method for preparing PAA/Graphene composite materials via in situ polymerization with graphene content of up to 50% for high performance nanocomposites. We study a method of effectively electrodepositing PAA/Graphene films on various metallic substrates and then curing them stepwise until complete immidization has taken place. Characterization

Structural defects are inevitable in graphene due to its production techniques as well as chemical and heat treatment processes. These defects in graphene are introduced either during the production process or deliberately by us to tailor its properties. In this article, the effect of nearest neighbour distance and angular orientation between Stone-Thrower-Wales defects (STW-2) on the mechanical properties and failure morphology of graphene was investigated in the frame of molecular dynamics. Mechanical properties and failure morphology of graphene was predicted to be the function of angular orientation between STW-2 defects, when the nearest neighbour distance was in the range of 10 Å. Graphene sheet containing pair of STW-2 defects had shown an overall increase of 8% and 11% in fracture strength and strain respectively as compared to graphene with single STW-2 defect. This study also characterised the failure morphology of graphene sheet with single and pair of STW-2 defects in the armchair direction.

Due to outstanding properties, graphene got more attention by the scientific community; all its exceptional properties are owing to hexagonal monolayer of honeycomb lattice packed with carbon atoms. The mechanical properties of graphene have been investigated using various experimental, theoretical and computational approaches. By experimental based work, Lee et al. [1] estimated the mechanical properties of graphene such as Young’s modulus of about 1.0 ± 0.1 TPa and fracture strength of 130 ± 10 GPa. Frank et al. [2] estimated Young’s modulus of 0.5 TPa for 2 to 8nm thickness of graphene sheets. Zhang et al. [3] measured Young’s modulus of 0.89 TPa for single layer graphene sheet. Besides experimental work, numerous theoretical and computational studies have been carried out to investigate mechanical properties of graphene. By orthogonal tight-binding method Zhao et al. [4] estimated Young’s modulus of 1.01 ± 0.03 and fracture strength and strain of 107 GPa and 0.20 in zigzag direction and 90 GPa and 0.13 in armchair direction respectively. By Ab initio calculation Liu et al. [5] estimated young’s modulus of 1.05 TPa and also estimated uniaxial tensile stress of 121

New materials with distinctive properties are arising and attracting the scientific community at regular intervals. Stiffness and strength are the important factors in determining stability and lifetime of any technological devices, but defects which are inevitable at the time of production can alter the structural properties of any engineering materials. Developing graphene with specific structural properties depends upon controlling these defects, either by removing or deliberately engineering atomic structure to gain or tailoring specific properties. In the present article, a comprehensive review of defective graphene sheets with respect to its mechanical and thermal properties are presented and examined.

ABSTRACT: One atom-thick sheet of carbon discovered this century is flaunted not just for its electrical properties but also for its physical strength and flexibility. The bonds between carbon atoms are well known as the strongest in nature, so a perfect sheet of graphene should withstand just about anything, but to use it in real-time applications, we have to understand the useful strength of graphene. So for, researchers have looked extensively at graphene’s electronic properties and tensile strength, nobody, had taken comprehensive measurements of its ability to withstand a compressive load. We find that, counter to standard reasoning, graphene sheets with Stone-Thrower-Wales (STW) defects are able to bear high compressive stress as compared to pristine graphene. We show that this trend can be understood by considering the critical bonds in the seven and five-membered carbon rings which bears the maximum compressive stress. Graphene with STW defects is stronger in compressive strength point of view because they are able to better accommodate these strained rings. Our results provide guidelines for designing graphene with STW defects to obtain maximum compressive strength, so that we can get the benefit of this

Stone-Thrower-Wales (STW) defect also referred as pentagon-heptagon-heptagon-pentagon (5-7-7-5) defect is formed by rotating a C-C bond by π/2, which transforms 4 hexagons into 2 pentagons and 2 heptagons as illustrated in Fig.1. Due to hexagonal and symmetric geometry of graphene system, only two types of STW defects are possible, STW1 and STW2 defects that are explained with the help of Fig.1. One of the main feature of graphene with STW defects is that it retains the same number of atoms as the pristine graphene, and also forms without creating any dangling bonds.

Diamond-like carbon is a class of amorphous carbon material which displays some typical properties of diamond. This material is often applied as coating to other materials so that it can benefit from some of the material properties of the DLC (diamond-like carbon). It is known that one of the properties of a DLC is a high hardness, which, on the other hand, makes it difficult to bond the material to most metals. Some processes are known to tackle this problem, which we will discuss later. [1]