Question

in ADDITION TO LARGE OR INTERFACE AREA, ANOTHER ADVANTAGE OF SEMICONDUCTOR NANOPARTICLE IS THAT ENGERY GAP CAN BE TUNED VIA PARITICAL SIZE at nm levels, use a equation to briefly explain how engery gap of an nano particle is correlated to its sizes

Answer 1

Using effective mass approximation, we write an equation

Where E(R) is the band gap energy , is the band gap of the bulk semi-conductor, and is the effective mass of electron and hole, R is the radius of the Nano particle with dielectric constant .

Electrons in the conduction band and holes in the valence band are confined by a surface potential. Hence, electron-hole recombination energy or the lowest energy transition from valence band to conduction band increases in energy. Hence band gap increases with decrease in particle size.

h2 1 1.8e2

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