Ultimate Scaling of the Metal-MoS₂ Interface Achieving High Performance Nanoscale Schottky Diodes via Conductive Atomic Force Microscopy

Ultrascaling of Schottky diodes is a key challenge of modern nanoelectronics. Recently, typical approaches have focused on the use of vertically stacked 2D van der Waals layered materials (2D vdWLMs), yet lacking deeper insights into the effect of vertical and lateral scaling to the nanoscale on Schottky diodes. Here, the study demonstrates high-performance nanoscale Schottky (nano-Schottky) diodes using conductive atomic force microscopy (CAFM), which simultaneously enables a reduction in diode length and the scale of Schottky junction within the metal tip-MoS₂-ultraflat Au structure. The nano-Schottky diodes, which range from 0.65 to 19 nm, exhibit an outstanding rectification ratio of 19.6 for 4 layers (4L)-MoS₂ and record high on-current value of 2.93 × 10⁵ A cm⁻² for the 9.9 nm-thick MoS₂ due to their ultrascaled structure. Furthermore, the nano-Schottky junction is demonstrated as a photodiode, showing distinct behavior depending on the diode length, the wavelength, and the power of the incident light. The study analyzes the underlying mechanism through simulations of the depletion region according to electrode size. These results not only lead to deeper understanding of the carrier transport mechanisms and optoelectronic properties of nano-Schottky diodes, but also provide novel tools to investigate carrier behavior or light-matter interaction at nanoscale volume.