Triple-crystal zinc selenide nanobelts

One-dimensional ZnSe nanobelts with three-dimensional triple-crystal architecture have been fabricated on Au-coated Si substrates by thermal evaporation of ZnSe powders. The as-synthesized triple-crystal ZnSe nanobelts are a metastable 2H-wurtzite structure while the typical structure of ZnSe nanocrystal is a stable zinc blend. The triple-crystal nanobelts have a typical length of tens of micrometers and a thickness of 30-80 nm. The morphology and growth mechanisms of the triple-crystal nanobelts, which cannot be described by the commonly used octahedral multiple-twin growth model for similar nanostructures, are investigated and explained based on the {1013} twins and two fastest-growing directions of [0001] and [1100] of the belt. The thermodynamics of the formation of metastable wurtzite ZnSe nanostructures are also discussed in terms of the temperature and surface energy. The photoluminescence spectra show that the triple-crystal nanobelts possess high-quality crystalline structure.