Modeling of Shape and Size Effects for the Band Gap of Semiconductor Nanoparticles

On decreasing size down to nanoscale, the physical, optical and quantum mechanical properties of the materials no longer remain constant but become tuneable. In order to understand these unusual properties of nanomaterials, some theoretical models and experiments have been proposed from various perspectives. The explanation of energy band gap increment can be presented in terms of quantum confinement effect. A simple model based on cohesive and activation energy, free from adjustable parameters to calculate the size and shape dependent band gap expansion is derived for the semiconductor nanocompounds. The model predicts that the energy band gap increases on decreasing the size of the particle of nanomaterial semiconductors. Also, it is seen that the effects of shape alter the band gap energy of nanomaterials and this effect on band gap energy becomes larger with the decrease in particle size. Our predictions are very consistent with the available experimented data and the simulation results.