ELECTRONIC-STRUCTURE OF SEMICONDUCTOR NANOCLUSTERS - A TIME-DEPENDENT THEORETICAL APPROACH

We present a time dependent theoretical approach to calculating the electronic properties of semiconductor nanoclusters. The technique can be applied to ground and excited electronic states without using the effective mass approximation or perturbative expansions. The effects of surface properties on the electronic structure can be calculated at an atomic level. We illustrate the method with calculations of ground state densities of states for CdS and CdSe crystallites between 19 and 33 angstrom in diameter. The size-dependence of the bandwidths and band gap is studied, and the influence of surface states and surface polarity is discussed. The calculated shift in the valence band edge with cluster size is compared with experimental results from valence-band photoemission. Good agreement is obtained.