Semi-empirical tight binding method for calculating energy levels of hydrogenated silicon nanoclusters as a function of size

چکیده مقاله

A semi-empirical tight binding model is used for calculating energy levels of spherical hydrogenated silicon nanoclusters in the form of Si_mH_n and two independent bases. The first basis is the nearest neighbor approximation of sp³s^⁎ orthogonal basis and the second basis is the third nearest neighbor approximation of sp³ nonorthogonal basis. Also, bulk properties of silicon crystal are used in the calculations. As we expected, obtained results show that the change in the size of nanoclusters has a great influence on their energy levels. So optical properties of these nanoclusters can be controlled externally. A comparative study on the calculated results and experimental results also reveals a good agreement between the two approaches.