Experimental evidence of ZnS precursor anisotropy activated by ethylenediamine for constructing nanowires and single-atomic layered hybrid structures

Abstract

Size and phase-controlled growth and assembly of semiconductor nanostructures from ultrasmall building blocks are of great significance in aspects of both science and engineering. In this work, ZnS nanostructures including nanoparticles, nanobelts, single-crystal nanowires and layered ZnS(EN)_0.5 hybrid structures are flexibly synthesized in a one-pot solvothermal system using ethylenediamine (EN) as the sole coordination agent. Comprehensive structure characterization, especially including spherical aberration corrected STEM imaging under an ultralow current density (2.55 A cm⁻²), provides direct evidence that the role of EN molecules varies from being surface stabilizers to being internal bridging blocks with changing introduction procedures. When introduced after the formation of ZnS precursors, EN passivates the non-polarized facets of ZnS clusters and activates the anisotropic growth along the [001] axis of the ZnS clusters into 1D wurtzite nanowires. When it is added before the formation of the ZnS clusters, EN molecules serve as the bridging blocks yielding layered ZnS(EN)_0.5 hybrid structures through the connection of wurtzite ZnS (110) slabs. The layered ZnS(EN)_0.5 nanostructures turn into single-crystal nanobelts after the removal of the EN components.