Charge Detection of Perovskite Nanowires Filled Single‐Walled Carbon Nanotubes for CMOS ICs

Inner doping of semiconducting single-walled carbon nanotubes (s-SWCNTs) with 1D CsPbBr₃ nanowires enables powerful electronic modulation while preserving lattice integrity, crucial for nanoelectronics. However, characterizing these heterostructures-identifying CNT type, fill status, doping position, and charge effects at the individual level non-destructively remains challenging. Here, Kelvin Probe Force Microscopy (KPFM), Raman spectroscopy, and scanning electron microscopy (SEM) is employed, to positioning CsPbBr₃@CNT heterostructures. Doping induced potential change across the CNT and the polarity of charge transfer can be directly resolved by this method at individual CNT level and a positioning precision of 89 nm, reveals a CNT diameter-dependent doping effect, with surface potential difference peaking at ≈130 mV for CNTs of 1.3-1.6 nm diameter, linked to confinement-induced CsPbBr₃ phase transitions. This study further fabricates p/n-type field-effect transistors (FETs) on single CNTs with both doped and undoped regions, via a self-aligned top-gate process with low-work-function titanium (Ti) as the contact electrode. These devices demonstrate symmetric performance (on/off ratio > 10³) and enabling the realization of inverter with near-ideal voltage transition at half the supply voltage. The maintained device performance after 1 month storage confirms doping stability. These findings can advance the controlled synthesis and application of inner doped CNTs for high-performance nanoelectronics.