Interlayer Charge Transfer Induced Electrical Behavior Transition in 1D AgI@sSWCNT van der Waals Heterostructures

The emergence of one-dimensional van der Waals heterostructures (1D vdWHs) opens up potential fields with unique properties, but precise synthesis remains a challenge. The utilization of mixed conductive types of carbon nanotubes as templates has imposed restrictions on the investigation of the electrical behavior and interlayer interaction of 1D vdWHs. In this study, we efficiently encapsulated silver iodide in high-purity semiconducting single-walled carbon nanotubes (sSWCNTs), forming 1D AgI@sSWCNT vdWHs. We characterized the semiconductor-metal transition and increased the carrier concentration of individual AgI@sSWCNTs via sensitive dielectric force microscopy and confirmed the results through electrical device tests. The electrical behavior transition was attributed to an interlayer charge transfer, as demonstrated by Kelvin probe force microscopy. Furthermore, we showed that this method of synthesizing 1D heterostructures can be extended to other metal halides. This work opens the door for the further exploration of the electrical properties of 1D vdWHs.