Category: Nanophysics
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Transmission Electron Microscope (TEM)
Electron beams are capable of providing crystallographic information about nanoparticle surfaces and can also be used to produce images of the surface, and they play this role in electron microscopes. The Operation of Transmission Electron Microscope In a transmission electron microscope the electrons from a source such as an electron gun enter the sample. They…
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The Production of Nanoparticles through Pulsed Laser Techniques
Pulsed lasers can be used in the synthesis of nanoparticles of silver. Silver nitrate solution and a reducing agent are flowed through a blender like device. In the blender there is a solid disk, which rotates in the solution. The solid disk is subjected to pulses from a laser beam creating hot spots on the…
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How Nanoparticles are produced through Thermolysis
Nanoparticles can be produced by decomposing solids at high temperature having metal cations, and molecular anions or metal organic compounds. This procedure is termed to as Thermolysis. For instance, small lithium particles can be made by decomposing lithium azide, LiN3. The material is placed in an evacuated quartz tube and heated to 400°C in the…
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The Concept of Molecular and Supramolecular Switches in Computing
The lithographic methods used to make silicon chips for computers are approaching their limits in reducing the sizes of circuitry on chips. Nanosize architecture is becoming more cumbersome and more costly to make. This has motivated an effort to synthesize molecules, which display switching behaviour. This behaviour might form the basis for information storage and…
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The Unusual Optical Properties of Semiconducting Nanoparticles
While I have indicated “semiconducting nanoparticles” in the title, nanoparticles made of silicon, germanium or cadmium are not themselves semiconductors. A nanoparticle of Sin can be made by laser evaporation of a Si substrate in the region of a helium gas pulse. The beam of neutral clusters is photolyzed by UV laser producing ionized clusters…
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What is the Difference between Quantum Wells, Wires and Dots?
When the size or dimension of a material is continuously reduced from a large or macroscopic size, such as a meter or a centimetre, to a very small size, the properties remain the same at first, and then small changes start to occur, until finally when the size drops below 100 nm, where dramatic changes…