First Principles Study for the Optical Properties of the Most Stable small ZnTe Nanoclusters

The optical properties of the most stable Zn _x Te _y (x + y = 2 to 5) nanoclusters have been investigated based on a first-principles study. The geometries of ZnTe nanoclusters are optimized using the B3LYP-DFT/LANL2DZ approach. At the same time, the optical properties of the most stable structures of individual configurations are studied using the Time-Dependent Density Functional Theory (TDDFT). This study also takes the zero-point energy modification into account. The most stable nanocluster has been defined as the structure with the lowest energy when compared to other structures for the same values of "x" and "y." The instability of certain of the nanoclusters is caused by the existence of at least one imaginary vibrational frequency. With a few exceptions, most nanoclusters exhibit significant optical absorption in the ultraviolet range but slight optical absorption in the visible region. By these investigations, absorption occurs on the higher energy side of Te-rich nanoclusters and the lower energy side of Zn-rich nanoclusters in the majority of nanoclusters. In the experiments, it may be possible to grow the most stable nanoclusters.