Month: August 2023
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Black Body Radiation
When a body is heated, it seen to radiate; in equilibrium the light emitted ranges over the whole spectrum of frequencies v, with a spectral distribution that depend on the frequency or equivalently on the wavelength of light λ and on the temperature. Gustav Kirchhoff proved a theorem when he showed by arguments based on…
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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…