Wedge-Shaped Confinement-Driven Dual Single-Crystalline Core-Shell ZnO-MAPb0.97Zn0.03Br3 Epitaxial Growth

Abstract Single-crystal core-shell structures boast excellent physical and chemical properties for a wide range of semiconductor heterostructure devices. However, it is difficult to obtain a dual single-crystalline core and shell due to lattice mismatch and poor heteroepitaxial growth. Herein, pure single-crystalline ZnO-MAPb0.97Zn0.03Br3 core-shell structures were successfully prepared using a wedge-shaped confinement reactor. A ZnO microwire (MW) is used as a seed crystal, guiding the growth of perovskite in the reactor. 3% Zn2+ doping reduces interface repulsion and provides lattice-matching sites. The reactor’s wedge-shaped design generates a consistently upward capillary force. Additionally, heating at the higher end creates synergistic temperature and concentration gradients that suppress the Marangoni effect and provide an appropriate evaporation rate. Based on the balance of the above factors, the liquid interface is driven to move in a determined direction and promote crystal growth.