Narrow Results

Molecular dynamics (MD) and modified analytical embedded atom method (MAEAM) are used to study the effect of the cross-sectional shape on the nanowire (NW) premelting. The results indicate that the premelting phenomenon occurs far below the melting point. The temperature dependence of mean square displacement (MSD) shows that the shape effect on the premelting phenomenon is obvious. Based on the detailed analysis of the atomic configuration, the premelting activation energy (PAE), and the shape factor, we have further found that the cross-sectional shape has an important effect on the premelting mechanism of the NW.

A simple theoretical model is developed to study the effect of size and shape on the bandgap of semiconductor nanomaterials. It is found that bandgap increases by decreasing the size, which depends on the shape considered. The results obtained are compared with the available experimental data as well as with those based on earlier models. Different models predict similar trend of variations. However, such an excellent agreement with experimental data particularly in low size range using a simple model is never seen earlier. The model reduces the number of input parameters and includes more shapes as compared with earlier studies. This demonstrates the simplicity and wide applicability of the present model due to which it can be used to study the size and shape dependence of bandgap of different semiconductor nanomaterials of current interest in science and technology.