Polarity-Free Epitaxial Growth of Heterostructured ZnO/ZnS Core/Shell Nanobelts

Abstract

Surface-polarity-induced formation of ZnO/ZnS heterojunctions has a common characteristic that ZnS (or ZnO) is exclusively decorated on a Zn-terminated (0001) surface of ZnO (or ZnS) due to its comparatively chemically active nature to an O (or S)-terminated (000–1) surface. Here, we report a polarity-free and symmetrical growth of ZnS on both ZnO±(0001) surfaces to form a new heterostructured ZnO/ZnS core/shell nanobelt via a thermal evaporation method. Remarkably, the ZnS shell is single-crystalline and preserves the structure and orientation of the inner ZnO nanobelt with an epitaxial relationship of (0001)_ZnO//(0001)_ZnS; [2–1–10]_ZnO//[2–1–10]_ZnS. Through this case, we demonstrate that an anion-terminated polar surface could also drive the nucleation and growth of nanostructures as the cation-terminated surface by controlling the growth kinetics. Considering high-performance devices based on ZnO/ZnS heterojunctions, the current ZnO/ZnS nanobelt is advantageous for optoelectronic applications due to its single-crystalline nature and relatively more efficient charge separation along 3D heterointerfaces