Role of surface energy in nanowire growth

As research interest moves from micromaterials to nanomaterials and quantum structures, the surface energy of the structures has an increasing impact on the nanomaterial growth and its properties. In terms of the nanowire research field, the role of surface energy has been debated for years since both surface energy and supersaturation in droplets play a role in affecting nanowire growth, making it challenging to distinguish the role of surface energy from supersaturation. Recent advances in nanowire research have gradually revealed that surface energy, which was underestimated in the past, is as important as supersaturation during nanowire growth. Here, this review discusses the available basic concepts and thermodynamic models about surface energy in determining nanowire growth. Recent experimental findings show that surface energy can determine the nanowire growth phenomenon, including nanowire growth direction, morphology, crystal polytype, axial and lateral heterostructure. The impact of surface energy for both nanowire growth mechanisms, vapor-liquid-solid and vapor-solid, are discussed. Through this review, the aim is to clarify the current understanding of surface energy in nanowire growth and build a knowledge pool for future nanostructure and quantum structure synthesis using a surface energy engineering process.