Size and orientation dependent melting properties and behavior of wurtzite CdSe nanowires

The thermal stability and melting behavior of wurtzite CdSe nanowires have been studied by molecular dynamic simulation. The melting temperatures of CdSe nanowires show clear dependence on nanowires sizes and orientations. The overall melting temperatures of CdSe nanowires are much lower than that of bulk and will increase with increasing size. Compared with other oriented nanowires, the 〈0 0 0 1〉 nanowire possesses a better thermal and structural stability, which helps to explain why wurtzite type CdSe nanowires prefer to grow in 〈0 0 0 1〉 orientation during experiments. It is also found that the premelting of 〈0 0 0 1〉 and 〈101¯0〉 nanowires starts from the surface atoms, while the premelting of 〈21¯1¯0〉 nanowire starts from the interior atoms. This unique melting behavior for the 〈21¯1¯0〉 nanowire may be related to the interesting structure reconstruction during the heating process.