Fin effect enables self-controlled growth of nanowires

Poor length uniformity in nanowires synthesized by template-assisted electrodeposition remains a bottleneck to the development of nanowire-based energy and electronic devices. This fabrication method is inherently unstable, often amplifying non-uniform growth and making precise control difficult. In this work, we investigate how introducing a temperature gradient along individual Bi nanowires enables self-controlled growth that suppresses such instability and improves length uniformity. The temperature difference at the nanowire tips, induced by the fin effect, regulates the local growth rate of each nanowire, allowing the system to equilibrate toward uniform lengths. This approach not only enhances the feasibility of nanowire-based technologies but also provides fundamental insights into self-regulating growth mechanisms, offering new opportunities in materials science.