Size and Crystal Orientation-Dependent Thermal Behaviors of ZnO Nanobelts

We report the size and crystal orientation-dependent thermal behaviors of zinc oxide (ZnO) nanobelts revealed by transmission electron microscopy (TEM) and atomic force microscopy imaging. Direct observation of lattice evolution upon heating unveiled an increase in thermal expansion, yet a decrease of melting point with decreasing ZnO dimensions. Additionally, ZnO nanobelts exhibited orientation dependency on thermal behaviors. High-resolution TEM inspection together with molecular dynamics simulations jointly revealed severe lattice distortion and expansion at and near the nanobelt surface and strong orientation dependency on binding energy. These findings advance our understanding of nano-enabled properties and provide additional design guidelines for developing nanodevices.