Strain Self-Releasing Mechanism in Heteroepitaxy on Nanowires

The self-assembly of one-dimensional semiconductor heterostructures including core−shell structures and quantum dots (QDs) on nanowires (NWs) has attracted considerable interest because heterostructures as basic functional units play a key role in device physics. Herein, we theoretically revealed that a new physical mechanism, the self-relaxation of an epitaxial layer originated from a nanosized curve surface, works well in heteroepitaxial growth on the surface of NWs. The competition between the relaxation of islands and the self-relaxation of an epitaxial layer determines the epitaxial mode on the surface of NWs, i.e., core−shell or QD heterostructures. The agreement between theoretical predictions and experiments indicated that the proposed theory could be highly expected to be applicable to the controllable fabrication of NW heterostructures.