Linear and Nonlinear Optical Properties of GaN Nanoclusters

The linear and nonlinear optical (NLO) properties of III-V binary semiconductors have been a subject of active research since the late 1960s. Recent advancements in (a) experimental techniques to fabricate/produce stable nanometer-size binary atomic clusters composed of group III and group V elements and (b) techniques and tools to probe response properties of nano-scale objects, have attracted a great deal of attention in the linear and NLO properties of III-V nanoclusters due to their potential applications in future technologies. An important issue in a bottom-up approach to fabricating nanoclusters for future technological applications is an understanding of the evolution of response properties with cluster size. In order to develop such an understanding, we have undertaken a systematic study of the electronic and geometrical structures and the optical properties of III-V nanoclusters by first-principles \textit{ab initio} time-dependent Hartree-Fock calculations. In this talk, we present the results of our first-principles quantum mechanical studies of the electronic structure, stability, and linear and NLO properties of Ga$_{m}$N$_{n}$ atomic clusters, with values of $m$ and $n$ ranging between $1 $and $17$. Our calculated results suggest that the linear and NLO properties both exhibit strong dependence on the cluster size and shape. However, the size-dependence is more pronounced for the NLO properties than that for the linear optical properties.